"I would have everyone write what he knows, and as much as he knows, but no more; and that not in this only, but in all other subjects: For such a person may have some particular knowledge and experience of the nature of such a person or such a fountain, that as to other things, knows no more than what everybody does, Cleaning Microscope Slides and Cover-will undertake to write the whole body of physicks, a vice and yet, to keep a clutter with this little pittance of his, Glasses.-Dr. J. B. Nias says: "Bacteriologists from whence great inconveniences derive their original." and others who find themselves with accumulations-Montaigne's Essays. of microscope slides may be glad of the following

hint for cleaning them. It is not given in any WHY ETHER? NON-ACHROMATIC textbook that I can discover. Instead of warming the slides one by one over a flame, pushing off the cover, and then scraping away the balsam and cleaning with alcohol, I put all my slides together into a saucepan with a lump of washing soda, and boil them. The heat of boiling is enough to soften most cements and all ordinary resins used for mounting, and I then fish out the cover-glasses one by one, push off the covers, and put them back. The action of the soda is to convert the balsam or

name of common sense, are powerful" reflectors,
and how can you convey anything from them-
whether "powerful" or not by means of wires
which are misnamed "electric"? Perhaps Mr.
Eldridge will give his ideas some definite shape, and
perhaps Mr. Edison will also exploit his. The fol-
lowing letter, by "A Constant Buyer of the
E.M."" is very much ad rem. What is the use
of the phonograph, and what will be the use of the
kinetograph, assuming that the descriptions of it
are accurate? Who will rig up a screen to see an
opera or a play in his sitting-room?
Nun. Dor.

་

confiance dans les résults de M. Schiaparelli et nourrit il pas un bien vif désir de voir sombrer réédite, sous une forme de plus en plus pittoresque, cette idée préconçue; 4° supposant que B, soit les reproches quil m'a déjà adressés à ce sujet."F.R.A.S."; 5°, soit aussi l'extreme difficulté de J'aime à rappeler que cet écrivain m'a autrefois, l'observation qui rend la constatation dont il s'agit dans ces colonnes, accusé de gober, en quelque très pénible. Qu' arrivera-t-il? B regardera cinq sorte, les yeux fermés, toutes les nouvelles de minutes et ne verra rien; il a la partie celle; je ne Milan; les occasions de s'égayer bien sincèrement vois rien ! les canaux n'existent pas! A, après cinq sont trop rares pour ne point en faire profiter une minutes d'insuccès, ne se tiendra pas pour battu, et, fois de plus les lecteurs de "l'E.M." Ce passage de grâce à sa foi, à sa volonté de voir, persévèrera peut"F.R.A.S.," a eu le privilége de dérider bien des fronts être une heure durant: à ce prix seul on peut austéres et j'invoquerai seulement ici le témoignage espérer un résultat. Voilà ce que j'ai voulu dire et d'un illustre astronome, l'un de mes plus bien ce que "F.R.A.S." doit savoir aussi bien que moi. veillants correspondants, qui m'a avoué n'avoir pu Ne sait il pas aussi que M. Stanley Williams, à s'empêcher d'en sourire pendant une journée sidérale Burgess Hill, M. Guillaume, à Péronnas, M. Schætout entière. Je crois en toute sincérité que le berle, au Mont Hamilton, M. Pickering, à Camnouvel article de "F.R.A.S.," aura un effét bridge ("E.M."), ont verifié l'existence des canaux MR. SLADE AND HIS DEMONSTRAanalogue, mais prolongé cette fois au moins que M. Schaberle, M. Williams, et M. Guillaume pendant toute la durée d'un jour solaire Mayeu. en ont même va le dédoublement? Il connaît Un autre astronome anglais, le Capitaine aussi la confirmation apportée par M. Perrotin, de Noble, qui semble en parfaite communaute Nice: il passe sur tout cela, et, qui sait? Peut-être d'idées avec "F.R.A.S.," avait jugé à propos va il même jusqu'à partager. L'opinion de cet de confier à la B. A. A., dans une de ses dernières autre adversaire des canaux, le Capitaine Noble, qui séances, avec un plaisir contenu, qu'un astronome pretend éternellement, qui va répétant partout du Continent avait démontre l'exactitude de la que M. Schiaparelli a annoncé la disparition de la période de De Vico. Parlez de la sorte solennelle-Libye alors que cette même Libye était restée ment avant l'apparition du mémoire, sur un simple visible au Mont Hamilton. Qu'on me permette de bruit, c'est, pour le moins, montrer un louable le dire, c'est là un "mare's nest vraiment empressement à accueillir les nouvelles qui caressent remarquable. Jamais, Jamais M. Schiaparelli n'a légèrement ses propres aspirations. Ainsi procède, annoncé la disparition de la Libye; que M. Noble aussi F.R.A.S.,"et, ayant à peine lu ou compris prouve son allégation si cela lui est possible. Or les pièces qu'il a sous les yeux, il rédige dans c'est l'origine de sa mèfiance a l'égard des résultats "I'E.M." un compte rendu où, pour ce qui con- de Milan, à juger par la passion avec lequelle il cerne le fond de la question, il y a beaucoup d'in- s'en va propageant partout cette erreur flagrante. exactitudes. Je n'aurais aucune peine à le prouver; Comme conclusion et pour nous résumer, nous mais je me contente de laisser les lecteurs se croirions la cause de l'astronome de Milan bien près former leur opinion eux-mêmes, pourvuque ce d'être gagnée si M. Green, invoquant le secours que soit seulement par les documents authentique et en se prêtent mutuellement toutes les branches du ne tenant aucun compte de la chronique en question. savoir humain, n'avait récemment cherché aussi à Je dois au moins légitimer cette restriction par ébranler la confiance en M. Schiaparelli, en quelques examples. FR.A.S," ignorant appa- invoquant à l'appui de son incrédulité les principes remment tous les usages de l'espèce, parait trouver de l'art dont il est un représentant des plus singulier que le travail ait été soumis à des com- autorités. F. Terby. missaires avant son impression; il trouve encore plus étrange, que le mémoir paraisse précédé des rapports de ces commissaires; voici un mot d'explication: si nos rapports précédent le tiré à part, ce ne peut-être que selon le vou exprimé par M. Niesten lui-même qui aura voulu loyalement réunir en une brochure toutes les pièces relatives à la question; cette résolution de M. Niesten sera approuvée, hautement louée par tous les lecteurs impartiaux. Mais voici bien une contre-vérité éclatante; mon honorable et savant confrère, M. Folie, dans son rapport, est bien loin de prendre parti pour M. Schiaparelli, il ne cache point sa sympathie pour l'opinion de M. Niésten, il va jusqu'à dirè que, malgré l'autorité du savant de Milan, une seule observation incontestée du genre de celles que cite M. Niesten suffirait à renverser l'opinion de M. Schiaparelli, et il considere si peu la question comme jugée qu'il manifeste l'intention de faire poursuivre cette étude au nouvel observatoire d'Uccle. Et savez-vous ce que F.R.A.S." a entendu de ces paroles de M. Folie? Pour lui le Directeur de l'Observatoire de Belgique considère toute difference d'opinion avec M. Schiaparelli, toute contrediction avec ce savant à l'égal d'un jet des pierres lancé à l'image d'un saint!

Et tout le reste est à l'avenant.

N'adoptant pas la maxime pratiquée par les hommes de science en général, car la généralité se distingue par une certaine tolérance et une certaine largeur de vuet, maxime qui prescrit de fermer les yeux sur les opinions religieues comme sur les convictions politiques des collègues, "F.R.A.S.," affectionne de lancer de petites pierres, à ce point de vue, sur la tête de ses adversaires du moment; souvent l'on rencontre dans sa prose les mots saint, miracle, aussi souvent que certaines autres expressions caractéristiques, tellesque "mare's nest," &c.-expressions que, pour ses écrits, sont l'équivalent d'une signature, et qui suffiraient à le faire reconnaître même sous un autre pseudonyme. Je n'ai garde de faire ici le hors d'oeuvre de laisser entrevoir, en quoique ce soit, mon opinion, comme lui, sur ces sujets; mais je me ménage cette transition pour préparer insensiblement le lecteur à cette terrifiante révélation que la foi que j'ai en M. Schiaparelli serait mieux en situation vis-à-vis des miracles de Lourdes! Voilà bien le style de mon honorable contradicteur; les lettres F.R.A.S." manqueraient qu'on saurait encore que c'est lui.

J'ai dit et je répète encore ici que pour réussir à constater la présence des canaux de Mars, il faut la for et de plus la volonté de voir. Ce mot foi a éveillé la susceptibilité du collaborateur de "I'E.M.," et suffit pour amener malgré lui sous sa plume une allusion à la foi Catholique, qui n'a rien à voir ici non plus que les pélérinages de Lourdes; "F.R.A.S.," au fond doit comprendre parfaitement le sens de la phrase que j'ai employée, quoique toute explication sont ici bien superflue; je donnerai cependant l'interpretation suivante qui n'apprendra risa aux astronomes: 1° soient deux observateurs A at Bse proposant de vérifier la découverte des canaux de Mars; 2° A a la foi, n'en déplaise à "F.R.A.S.," et le désir ou même la volonté de voir; 3B n'a pas la foi, il considère les canaux comme un produit de l'imagination et peut-être ne

A LONG APOLOGY FOR A LITTLE SLIP.
[32495.]-IN the issue of the "E. M." of the
26th ult., I observe that your correspondent
"F.R.A.S." has devoted some portion of his
valuable time and of your valuable space to my
humble self, by directing attention to a letter,
which appeared above my name, in our local press,
on the 5th ult., relative to the pending annular
eclipse of the sun predicted for the following day.
It was my misfortune to make a lapsus calami in the
transposition of the words east and west, as it was
also my misfortune not to detect the slip until it was
too late to correct it. However, the veriest tiro in
astronomical matters must have at once seen that
it was a mere slip of the pen; and "F.R.A.S."
need not, I am sure, suffer the slightest uneasiness
as to the chance of anyone being led out of the
orthodox track, on the question of the direction of
the path of our satellite in the heavens, by anything
which may have appeared in my letter. In our
own city, I am happy to say, we have some astro-
nomical talent, not very vastly inferior to
that of your unquestionably talented corre-
spondent F.R.A.S.," and it is quite clear
that my lapsus calami did not here interfere
much with rest or appetite, otherwise my letter
would doubtless have received some attention in our
local papers, and I cannot, therefore, say that I am
altogether obliged to your able correspondent for
having given quite so much prominence to my
name, in a paper having such an immense circu-
lation as the ENGLISH MECHANIC, a paper which is,
in fact, read all over the world, on such a miserable
puerile point as a trifling slip in an item of cor-
respondence which appeared in a provincial paper.
It is within my recollection that "F.R.A.S." has
himself ere now been corrected by some of your
correspondents, and on certainly more than one
occasion. Humanum est errare, but "people who
live in glass houses," &c.; and, in conclusion, I
would only say to "F.R.A.S." that, as absolute
accuracy ought to be observed, even by critics, he
might-in referring to myself and to my letter-
have given my proper name, which is, as I appended
it to the letter in question, not Redfern Kelly, but
Wm. Redfern Kelly.
Hon. Sec. Ulster Astronomical Society.
Belfast, July 2.

TION, "ON THE SANDS." [32497.]-"F.R.A.S." remarks: "Without attempting to disparage Mr. Slade's demonstration of the character of the moon's path in her orbit, as referred to the sun I would humbly venture to submit that in a letter of my own (69827, p. 307, Vol. XVIII.) I showed, in the succinct form of a single paragraph, everything that your correspondent occupies three columns and a half in explaining.' This is really a disparaging and misleading statement. All that "F.R.A.S.' shows, is the fact that the moon's path from last to first quarter is concave to the sun, and this he does very clearly with the aid of a simple diagram and some half-dozen lines of letterpress. But my diagram gives the path of the moon, drawn to scale, for an entire lunation, showing its position in its orbit for every twelve hours. The accompanying letterpress occupies one and a half (not three and a half) columns, and, in addition to describing fully and simply the method of construction, deals with the moon's axial rotation and libration. I therefore repudiate the insinuation that I have been guilty of verbosity. I have purposely gone into details and introduced the Nautical Almanac, so that intelligent seamen, as well as amateur astronomers, might find no difficulty in mastering the subject for themselves. My object is to make quite clear to others what I understand myself, and, in view of the rapid accession to the astronomical societies of the rising generation, not to fall into the error of crediting them with knowledge which they do not possess. Perhaps "F.R.A.S." will pardon me if I take up a few more lines of your valuable columns. Last Friday morning an astronomical friend and I describing a circle of 3434in. radius on Filey sands, laid down from the N.A. a portion of the orbits of the earth and moon round the sun, commencing with Jan. 10, 1891, and ending with March 25, 1891. We indicated the position of the earth in her orbit by holes in the sand, and the cycloid path of the moon by a line of matches. The curves in moon's orbit were beautifully exhibited. I would suggest that amateur astronomers should utilise the sands this summer for the same purpose; and if they do, I humbly venture to think a paragraph of six lines will not help them much-i.e., if they are as much at sea on this subject as it appears some astronomers are. H. P. Slade, F.B.A.S.

THE ADDITION OF CANE SUGAR TO

MALT WORTS.

[32498.]-THE method employed by the Somerset House authorities is, I believe, the second mentioned by Mr. Wilson (letter 32484): polarising wort before and after treatment with invertase, which body is said to invert the cane sugar alone, leaving the other sugars unaffected. This is the process given in Mr. Hooper's work on Brewing, and he is one of the Somerset House chemists. In the case of a mixture of pure sugars, it would be a difficult matter to estimate a small quantity of cane sugar to half a percentage, whilst in a malt wort the difficulty is immensely increased by the nitrogenous constituents, which are continually undergoing change during the mashing process, and about the action of which on the polarimeter we know next to nothing. There is also the difficulty of being sure that the small samples usually taken for experimental purposes adequately represent the bulk, a point on which I have grave doubts. Mr. O'Sullivan gives the amount of cane sugar found in malt as varying from 2.8 per cent. to 6 per cent.; consequently the amount of cane sugar found in the Stockport wort was just within the limits of probability. Personally, I should be very sorry to swear to such a small quantity as per cent. of cane sugar in a wort, and if the Somerset House authorities pursue this course, they will, sooner or later, find themselves in the invidious position in which they have found themselves before this, in cases of disputed food analysis referred to them. W. J. Sykes, M.D.

THE KINETOGRAPH. [32496.]-IT seems to me that Mr. Edison must suffer muchly from the "greatness" which has been thrust upon him. Would it not be as well if some of your correspondents waited to see what the kinetograph can do before claiming prior invention? So far as I understand the matter, it seems to me that what Mr. Rudge (p. 406) says nothing whatever to do with it, though it may be LAMP CHIMNEYS AND GLASS WARE. quite true that "life-like effects on a screen were [32499.]-OUR friend "Glatton's " letter (p. 406) produced some years ago, as, if my memory serves, they were at the Polytechnic when I was a boy. The remarks of Mr. Eldridge (p. 406) are ludicrous. His idea was to convey by powerful reflectors from mirrors by electric wires," &c. What, in the

has

is interesting, especially as it adds another instance to the unbecoming behaviour of glass ware; but I am afraid that the experience of the "housewives" he mentions cannot be received as scientific evidence. My better-half has baked the chimneys for

ENGLISH MECHANIC AND WORLD OF SCIENCE: No. 1372.

hours, and boiled them as described, often and
often; but still they "go." I fancy that the glasses
which don't "go" after the boiling would not have
"gone" if they had not been boiled; but that is not
the point. What I want to get at is some possible
explanation of the fact that lamp chimneys, after
they have been in use for months, "go" in the most
unceremonious manner-without
warning. Some of the commonest chimneys,
the slightest
neither baked nor boiled, last for months; others
boiled in exactly the manner described by "Glat-
ton" last for a time, and then suddenly crack.
Clearly annealing has something to do with the
durability of the chimneys; but the puzzle (to me,
at least) is that they should sometimes last so long,
and then break up the acquaintance just as they are
beginning to be trusted. I do not think the tem-
perature of boiling water can do much in the way
of annealing glass, and prefer putting the chimneys
into the oven; but still they crack. What has be-
come of that hardened or tempered glass? It seems
to have gone quite out of fashion. Saml. Ray.

LAMP ACCIDENTS.

[32500.]-THE ENGLISH MECHANIC 19th June most kindly published a short memo. by me on petroleum, in which I stated that if it were cold to the fingers, it would not readily take fire; but if warm, it would take fire instantly. Having for many years noted the awful destruction of life and property, almost of daily occurrence, from the accidental overturning of mineral oil-lamps, I set my ingenuity to discover a remedy, and now I claim for my labour a success deserving every notice, since it is most real and effective.

On finding "vulcanised fibre" to be an exceed ingly tough material, impervious to most things, including oils, and the most effective obstructer to the passage of heat known to science, I tested it for wick-tubes; and on finding it most effective in every way, I obtained a "patent," dated 16 June, 1890, which is now very protective against infringement for years to come.

To all the lamps that I showed in the Military Exhibition of last year, I adjusted my "vulcanised fibre" tubes, and in recognition of their great merit, "the science committee" conferred on me the honour of "the diploma of merit."

Now for a few telling words-short, sharp, and to the point. Mineral oils are apt to be the temperature of the place where they are kept, say, 65° F. on the average of the year; but to-day, it is 72° F. Well, then, after two hours' burning with a brass wick-tube, the temperature of the oil in the lamp reservoir may increase by 20°, 30° F., or more degrees; thus bringing it up to the extreme danger of 100° F., or more, and within an inch or so of the hot burning wick-flame a little above it.

As I was a pupil of that highly intellectual man, Michael Faraday, perhaps I can reason just a little; so for the benefit of my fellow countrymen I urge, discard all mineral-oil lamps fitted with metal wicktubes and adopt vulcanised fibre wick-tubes, since they keep the oil cold to the fingers; or, in other words, they never add even five degrees (5° F.) to the burning oil-ergo, they are really "safety tubes." In practical illustration I have it on record in my diary that petroleum at 64° F. increased its temperature during only two hours' burning, as follows: With brass wick-tube to 88° F., increase 24° F.; with vulcanised fibre tube to 68° F., increase 4° F. -i.e., 20° cooler.

Now the official report open before me, dated Home Office, 28th April, 1890, shows that of 28 accidents, as many as 12 occurred with oil superheated to the average temperature of 84° F.; the greatest heat named being 110°-viz., at Ovingdon Gardens, the late Lord Romilly's house that was lately burnt down, and in which he lost his life by the upsetting of a mineral-oil lamp.

J. D. Shakespear, Colonel late R.A., &c., A.M.Inst.C.E. 25, Great George-street, S.W.

WINDMILLS.

[32501.]-I THINK Mr. H. Morgan (letter 32470) has spoken rather strongly against the revival of windmills. Of course, as he says, a steady wind is wanted; but how is it that years ago most grinding was done by using wind as a motive power? Certainly they could not always have had strong winds; but they seemed, at any rate, to have got on pretty well. I do not think myself that windmotors will ever compete with electricity or steam; but wind has, as everyone, I think, will acknowledge, one nothing to make it do its work. There is a wind "great" advantage, and that is, it costs apparatus used for pumping made by Picking, Hopkins, and Company, sketch of which, I am afraid, would take up too much of the valuable space in the ENGLISH MECHANIC.

C. G. M. Bennett.

HISTORICAL LOCOMOTIVE. [32502.]-THE annexed diagram illustrates an old and interesting locomotive engine, built

by

Messrs. Carmichael and Co., of Dundee, and placed
upon the Dundee and Newtyle Railway, September,
1833, named Lord Wharncliffe. The cylinders were
11in. diameter, 18in. stroke, and the driving-wheels
4ft. 6in. diameter. Your readers will observe that
the engine is provided with a "bogie," this engine
only bogie engines in use in this country.
and two others upon the same railway being the
Leicester, June 27.

C. Stretton, jun.

JULY 10, 1891.

are easier without oil; but let our friend try to ride 1,500 on a eet without oil, and see the result. Science and knowledge cannot yet point out a mode of making bearings that are not improved by the oil film, and so long as the proportions of the surface to the weight are properly maintained, there is no difficulty in making the oil-film intact, and hence the nearest approach to frictionless motion. The consideration of the oil-film is outvehicle I am, from daily use, fully satisfied that side the present inquiry, and I leave it where it is, matters well enough. On a bicycle or other light because, as I understand, our friend is an engineer himself, and therefore knows all about such question I have briefly touched on-viz., the rela tion of surface to pressure. ball-bearings run easiest.

But there is the other

Vulcan.

yet wrong in his theory of the above, and I would BALL BEARINGS. [32503.]-MR. SHAKESPEAR, in my opinion, is of ball bearings-viz., the grindstone with friction wheels. From this the revolution passed through refer him to the earliest type of the present system many stages, notably into the form of frictionrollers, thence to balls or spheres. It is quite right have no lateral thrust, and then comes in the friction-wheels of the original grindstone. I am the authority of Mr. Preece, that there can be "no that the present ball bearings of good make not able to say from personal knowledge whether hanky-panky' with their accounts," meaning, I THE COST OF ELECTRIC LIGHTING. Mr. Shakespear is right or wrong in his statement presume, the accounts rendered to the Board of of the respective pressures on the balls, and there- Trade by the electric lighting companies: but it [32504.]-IT is interesting to learn (p. 402) on fore assume him as correct. But what is to be would be of more interest still to have some definite understood by " bind "; and, as a user of parallel information as to the statement that there is "not bearings, I have never found them bind or seize, a shadow of doubt that at the present moment the unless the surfaces ran dry and expanded, due to kilo-watt.... could be produced for 4d." On many years' standing, I cannot agree with him that does it mean that consumers of the electric light can the reason why engines are not fitted with ball have it at 4d., or that the price stated is merely the the rise of temperature. As a practical engineer of what figures or data is that statement made ?--and bearings is that of the expense. this as correct. My experience of building loco. little, the kilo-watt can be supplied at a low rate, and marine engines is that the area of the surfaces and the 44d. in Newcastle may pay; but I note that in contact with, say, the crank-shaft, must bear a cannot admit cost of production? Obviously, where coals cost known proportion, or heating will ensue. If, there- amounts to 74d., and even 8d. in London. What I fore, ball bearings were fitted to the main journals want to know is, how do the bills figure out as com of, say, a loço., it would need so many rows of balls pared with gas? It is all very well to tell us that that the bearing-case would be far too long to the electric light can be supplied for 8d., or even even according to Mr. Preece (as reported), it be got inside the frames between the crank-throw 5d. per kilo-watt; but what do the consumers' and the wheel-boss. It may be said: But with out- bills say as compared with those for gas? I canside cylinders there would be room. that direct driving of the valve-spindles would be note that he acknowledges that the electric light impossible. All these difficulties arise from the does cost more even there, after allowing for the eccentric sheaves would be so far from the frames saving at the Savings' Bank Department, but I do Then the not follow Mr. Preece in his statement as to the fact that to carry a given weight, a given bearing- extra work performed " surface must be employed. A loco. and a bicycle whatever that may mean. are not parallel cases, insomuch that the weight to of the ENGLISH MECHANIC who can give definite be carried differs, and as it would (assuming other information on the subject? matters were arranged) be impossible out of a units are, and the rates they are supplied at; but per head per annum," Is there not one reader number of ball races to get them all of the same how does the electric light shape when compared hardness, a time would very soon come when the with gas-bills? I do not pretend to understand We know what the greater part of the load would be carried on a small what Mr. Preece can mean by the " proportion of the balls. I do not think that ball-point of view. It is simply a question of economy bearing are therefore practicable for loco. engines, and convenience, and I should like to be informed bearings or railway waggons either as applied to cheaper than gas as supplied to consumers? or any large steam-engines. In my experience I how the electric light can, by any possibility potential" their axles, and the application of ball-bearings to have never met with counter-straps carried in ball- (taking the photometric standard as a test), be lathes and drilling-machines is so very limited that I do not take them into consideration. May I ask Mr. Shakespear if he has ever seen, say, a 12in. centre lathe made by any well-known English maker fitted with ball-thrust bearings, or, still further, a railway wheel turning lathe fitted with such?

running 1,500 miles without the oil squeezing out. lies as to a parallel bearing in. diam., 4in. long, I cannot see where Mr. Shakespear's argument Surely he would not expect any sensible rider to travel 1,500 miles with one oiling-up? Now, I have myself travelled over 2,000 miles on a plain bearing in. by 2in. long, and never had any seizing or binding, because I oiled up every 30 to 50 miles at most; nor did these bearings ever run perfect as far as coolness and minimum of wear hot. Engineers know by experience that bearings are concerned. It is quite true that ball-bearings double their diameters in length run practically

LATHE MATTERS. TO

Incans.

"EARLSWOOD

of American lathe for PARK." [32505.]-THANKS for promise of description work; there is the English mandrel, a simple lathe is no English combination lathe made for watch foreign tools; but then, same time I have become prejudiced against watch work. At the with face-plate (which is a permanent fixture), and slide-rest-no meeting centre. unfortunately, there a little better in this respect, yet too elaborate, considering the little use they can be put to, no proThe Swiss tools are vision for chucks, or turning arbors between centres. The chief objection I have to American lathes is to screw on nose of mandrel, and always run true! high price, and too complicated. Why have two Instead of draw-in spindle, I prefer a taper hole, headstocks? Is it impossible to have the face-plate

but I have never seen a word about them in an
English paper. Was this invented in England
too?
F. A. M.

STONEHENGE.

either in mandrel nose or a chuck that screws
thereon, for small chucks, centres, &c., all large
chucks to screw on mandrel nose; the step-chucks
I do not like. It is easy to turn a sink with a slide-
rest in a piece of sheet brass held in the dogs THE ASTRONOMICAL TRADITION OF
(having previously made a centre-mark for pump-
centre), to hold a wheel or barrel, and then shellac
it fast while truing holes; it is certain to be true. I
should like to see the man that could rebush a
barrel, top and bottom, also top and bottom holes
in frame, and the barrel be upright and run true
when finished. I have tried it with these draw-in
chucks, but failed. I think it a mistake to put the
screw of upper slide of rest outside: it imparts a
contrary effect to cutter, on turning the screw the
desired way. Suppose the cutter is cutting, and
you turn the screw to withdraw the cutter, you find
the side strain has caused it to take a deeper cut
instead.

But the most absurd thing about these lathes is that they supply no Jacot accessory for running watch pivots, and yet they supply one for running clock pivots. Now these lathes are for watchwork, not clock-work, so that you must possess the ordinary Jacot tool in addition to one of these lathes. In running in a cylinder, say, you would require to do part in the lathe and the remainder in the Jacot tool. That's what I call humbug. I fancy I can hear others in the trade say the same. I do not like cast iron for these lathes; they rust terribly as you are using them, with the breath. Brass or bronze would be better.

I have an ambition to arrange a lathe in aluminium bronze, 18in. bed, 1in. face, lin. deep, hollow mandrel for pump centre, 3in. centre. I should like to try a single taper of 12 per cent. for each cone of mandrel, instead of the double ones of 6 per cent. and shoulder of 45 per cent. Would it be liable to jam? Face-plate to screw on mandrel-nose. Is the seamless steel tubing advertised suitable for making a good hollow mandrel?

LATHE MATTERS.

G. H.

[32506.]-THE "E.M." contains a feast for lathe men this week.M." has certainly crowded a wonderful amount of interesting information into his excellent paper on "Lathe Attachments." With regard to Lord's taper turning attachment, will some one kindly explain what is the use of the two slides? The use of the upper one shown obliquely is evident; but what is the under one "Made in England" tells us it was used in England 25 years ago, and I should like to ask, if that is so, why it is we cannot have these things described for us at first hand in the "E.M.," without having to get English inventions filtered through the American Machinist? This is a thing that I have puzzled over many a time.

for?

found was a risky and painful operation, and I sought to improve on it. I simply took a file and carefully filed a groove into the flat surface of the nail right through the tip, parallel to the length of the toe, and all but down to the quick (very gingerly as I approached it), taking care not to touch or wound the scarf skin. The pressure is removed, and relief is almost instantaneous. Your correspondent's theory was that Nature, out of "pure cussedness," would fill the void so created, and the nail would therefore cease growing into the flesh at the sides. All I have to say is, try it. The method is painless and effective, and can be easily applied on any trouble arising again. Pede Claudo.

[32507.]-A FEW years ago some little discussion took place in your columns with respect to the tradition which ascribes a quasi-astronomical purpose to the builders of Stonehenge. The legend runs that on the longest day of the year, the sun, observed from the altar stone, may be seen to rise immediately over the summit of an isolated monolith, popularly known as "Friar's heel," standing at some distance outside the inclosure, and so planted that it occupies the centre of the WHEATSTONE'S BRIDGE. space seen through the entrance column, while its [32510.]-IN letter 32487, page 407, are the highest point is just level with the distant sky-line. following errata :-2nd column, page 407-15th line, With a view of obtaining, if possible, an actual"a" should be outside the bracket; 22nd line photograph of the phenomenon, I made a midnight should read bridging the gaps m, and m, carefully; pilgrimage to Salisbury Plain at the time of the last 28th line, there should be a period after the word solstice, accompanied by Mr. Thos. B. Howe, of "again." 3rd column, 40th line, expression within Newbury, a well-known professional photographer who has won a reputation for his skill in overcoming bracket should be 1 + 48th line, for "1,4440," many practical difficulties in his art. read, 1,440; last line, end of line, for "200," read 7,200. 1st column, page 408, read "and" instead of "x." I should also have said that my authority is Kempe, from whose book on testing I made extracts some years ago.

I inclose a photograph which will show what is
to be seen every midsummer dawn when clouds
are absent. We had no manifestations touching
the Devil or the Friar, or any other of the many
blood-curdling tales of this haunted ground, but as
to the truth and object of the above-mentioned
special orientation of the sentinel stone there can be
to my mind no room for doubt soever.
Newbury.

J. M. Bacon, F.R.A.S.

INGROWING TOENAIL.
[32508.]-I CANNOT help writing that for more
than forty years I have successfully adopted the
cure prescribed by "J. W.," of Birmingham, on my
ingrowing toe-nails.

as

I was a sufferer a long while, till necessity, being
the mother of skill, as we say here in Flemish, I
conceived myself the method recommended on
page 385: soaking the feet, and then taking a
sharp pen-knife, holding it in the right or left hand
thumb of the other hand, and cutting forwards.
a writing pen, supporting the nail with the
Besides, I let fall a little drop of acetate of silver
into the sinus between the nail and the flesh. There
is being formed a layer as of indiarubber, a sort of
small cushion, which will last several months as
preserver of the tender skin.

Maldeghem, Belgium, July 5.

a

[32509.]-I SEE in my monthly number some letters about ingrowing toe-nails. I owe the ENGLISH MECHANIC such a debt of gratitude for the relief I obtained that I should like to record my experience for the benefit of others similarly affected.

Do our lathe men know what is a centre in-
dicator, used for testing the truth of the running
centre, or for setting a piece of work true on the
face-plate to a centre punch dot, when a hole is to When I was suffering some years ago, one of
be bored in exactly the right position? Several your correspondents recommended cutting away
forms are described in the American Machinist, the centre of the nail with a sharp knife; but this

x

α

M. H. W. L.

WHILST the Union Steamship Company's new R.M.S. Scot was open for inspection at Southampton, she was visited by between 7,000 and 8,000 persons; and during a brief stay in the Royal Albert Docks, London, she was inspected by some 5,500 visitors.

Paraffin Oil and Alcoholism.-The number of remedies-not to say nostrums-which have from time to time been vaunted as specifics for alcoholism is legion, some of the latest being red cinchona, strychnine, ichthyol, phosphorus, hydrobromate of hyoscine, and hydrastis. The most recently suggested remedy is petroleum, or paraffin oil, to which the attention of the St. Petersburg medical that a labouring man, who had been drinking heavily authorities was called by an accident. It appears for four days and nights, entered in a complete state of intoxication a grocer's shop, without being conscious of where he was or what he was doing. Unnoticed by the shopkeeper, he staggered up to an open cask of petroleum, and began drinking from it. With difficulty he was dragged away from the cask, and, seeing the large quantity of petroleum he had imbibed, it was expected he would fall down senseless, and be seriously ill. Instead of this, however, it is related that the petroleum had cured him of all the ill effects of over-drinking, the nausea, unsteadiness of gait, and headache disappearing as if by magic. In fact, it is stated he left the shop sober, and quite another man as compared with what he was before he took the draught of petroleum.-Lancet.

REPLIES TO QUERIES.

In their answers, Correspondents are respect fully requested to mention, in each instance, the title and number of the query asked.

[74055.]-Electrical.-To "HYSTERESIS."-It is absolutely of no use continuing this polemic, since "Hysteresis" maintains that E.M.F. is altered by resistance, and I know that it is not. The experiment he suggests of the chromic acid cell, with and without porous partition, has been tried by me, with the result that, in either case, the E.M.F. comes out at two volts. What is altered is the ampèrage, which, owing to the resistance of the porous diaphragm, is lowered from 25 ampères on the short circuit in a 4in. cell, without diaphragms, to 3 ampères on the short circuit when the diaphragms are inserted. I am rather amused when Hysteresis" says: "How Mr. Bottone makes the E.M.F. of the Daniell cell 1.079, &c." I did not make it; it is so. The reference to perpetual motion and the Keely motor is out of place, because energy is expended in overcoming resist ance; hence E.M.F. opposed to a great resistance gives a small current, and E.M.F. opposed to a small resistance gives a large current, which is in accord with all dynamical principles. The current strength (ampères)" at the line of junction of the two fluids" is precisely the same as that at any

other portion of the circuit.

S. BOTTONE.

[74055.]—Electrical.-"Hysteresis," in reply to this query, makes several statements which ought to be contradicted. He says that "when we increase the internal resistance of a cell, the E.M.F. is reduced; and if the interal resistance be reduced, the E.M.F. is increased." Now the E.M.F. of a cell is the P.D. (potential difference) between its terminals when it is sending no current, and for any pair of elements immersed in a given liquid, this P.D. is constant, and does not depend in any way on the resistance of the cell. "Hysteresis must, I think, mean by the E.M.F. of the cell, the P.D. between its terminals when it is sending a current. This P.D. is equal to

=

troubles.

[74338.]

Eos.

Child Marriage in India.

"S. E. P.," in his reply this week, draws a terrible
picture of the immorality of native races, and then
deprecates the interference of "kindly old gentle-
men" in the British Parliament as likely to cause
the loss of India. This is just the kind of argu-
ment used at the time suttee was forbidden. Why
must we hear so often that we cannot impose
Western notions of morality on Eastern nations?
Is it, then, hopeless for England to try to raise the
standard of morality in India? Must there be no
progress under English rule, however slow? We
have taught numbers of natives in India the use of
drink and opium, and thereby done them frightful
harm; in the name of our common humanity, let
trying very gradually to introduce purer customs.
us back up the " kindly old gentlemen" who are
It is not by doing right that we shall lose India;
but by fostering, for the sake of revenue, the trade
in opium and spirits, and so interfering with the
habits of sobriety of the natives. F. A. M.

[74416.]-Slide Bearings (U.Q.)-You should
use cast iron. Wrought iron and gun-metal are
unsuitable for such a purpose.

Materniestr. 3, Dresden. A. F. SHAKESPEAR. information was gained from a mutilated advertise[74452.1-Compound Gas-Engines.-My only together with the address of the advertiser, had ment in a German paper, the name of which, been torn off. The cylinders were double-acting, the action much the same as an ordinary compound steam-engine minus "hot-pot," and supposed to be more economical than the usual double-cylinder engine.

bag 3, and 1 in 10 of bag 2; whilst not only 432, but many other shares from 100 to 499, have 4 in 5 of bag 3, and 9 in 10 of bag 2. Suppose 432 had been drawn, still any other high share-such as 257 or 389 would have a better chance than share 2 or any other share from 1 to 99. There is an exception in the case of shares containing an 0, for instance, 250, or 307, for in these cases the chances are reduced as against the chances of shares containing actua' numbers, say, 256 or 258, or 336 or 337, for whilst there is only one 0 in each bag, there are nine actual numbers in bags 1 and 2, and four actual numbers in bag 3. Altogether it seems to be a very pretty contrivance for giving the series of highest shares the greatest advantage, and for making certain shares, viz., those containing actual numbers, more valuable than those containing an 0.

H. BROCKLEHURST,

[74527.]-Melting Iron.-If "R. M." wants to melt iron, he will certainly require something in the nature of a cupola. He will find one in the number for Nov. 22, 1889, p. 255, and others that may perhaps suit him better in the issues for March 23, 1888, and June 22, 1888. I suppose he knows that melting iron is not an easy job, and that if he wishes to make a trade of "casting," he had better have a practical cupola builder to do the necessary work for him.

L. M. T.

[74552.]-Utilisation of Water.-A turbine would probably give the best results; but to form an idea as to the most economical method mors particulars must be supplied. NUN. DOE.

Materniestr. 3, Dresden. A. F. SHAKESPEAR. [74554.]-Plumbago Crucibles.-These are [74452.]-Compound Gas- Engine. 0-i.e., Much simply moulded up in the usual way. As to the depends on what the term "compound" is sup-question about the word "patent," I do not think posed to embrace. Compound gas-engines have it has been decided whether or not the word been invented, patented, and talked of much, but it "patent" may be appended to any manufactured yet remains for a practical and commercial one to article which has been protected by a patent for the be placed on the market. I could, by making search allotted time; but it is quite certain now that amongst old papers, find the blue books of some nothing must be described as patented until the and data as to one of these; but if "R." is wise, Great Seal has been appended to the specification. he will not bother himself about them. VULCAN.

where is the external resistance, the internal
resistance, and E the E.M.F. resistance as defined
above. V varies with b, and when x=
when the cell is short-circuited by a short, stout
wire, VO; or, as "Hysteresis" would have it,
the E.M.F. is zero. When x = ∞-i.e., when the
cell is on open circuit, V E. In support of his
assertion, "Hysteresis" gives us two most unhappy
examples. He tells us first to measure, by suitable
means, the E.M.F. of a cell consisting of two
metals in a liquid. Then the resistance of the cell
must be increased, and its E.M.F. again measured.
It will be found, says "Hysteresis," that the second
E.M.F. will be less than the first. Perhaps the
following figures, from an actual case, will convince
"Hysteresis" that he has made a mistake.
The cell consisted of plates of pure copper and
zinc, immersed in a saturated solution of zinc
sulphate. The E.M.F. was measured by Poggen-
dorf's method:-

1. Plates in. apart, E.M.F. represented by 5,694.

2.

3.

5,692. [74477.]—Solvent for Wood.-You should not ,, 5,690. have used the word "solvent." To do what you These figures show conclusively that the E.M.F. of require, boil the fragments of wood with caustic the cell is entirely independent of its resistance. soda in a closed iron vessel-that is, under pressure. His second example is a most alarming one. may be applied by means of steam. says, that when two cells of the same kind are [74517.]-Chances.-Bag No. 1 contains 10 balls joined so as to oppose one another, a current is sent-0, 1, 2, 3, 4, 5, 6, 7, 8, 9-bag No. 2 contains the by that cell which has the lower internal resistance. same, bag No. 3 contains 5 balls-0, 1, 2, 3, 4. The This statement is absolutely untrue. If the two holder of almost any share between 100 and 499 has cells are made of exactly the same metals and a better chance of being drawn than the holder of a liquids, there will be no current whatever, no share from 1 to 99, for there are 4 chances in 5 that matter what the internal resistance of each cell may a share containing an initial number of 1, 2, 3, or 4 be. For, since the cells are opposed, the total will be drawn; whereas a share from 1 to 99 has E.M.F. in the circuit must be zero, and the current, only one chance in 5 that the 0 will be drawn, which would reduce the draw below 100. The series of shares numbered over 100 have an even greater

Materniestr. 3, Dresden. A. F. SHAKESPEAR. [74172.]-Lathe Chuck (U.Q.)- Gun-metal face-plates do not do for the American chucks, as a rule. Send it to a tool-maker, and get it mounted on a cast-iron plate, or you can do it yourself if you have a screw-cutting lathe.

Materniestr. 3, Dresden. A. F. SHAKESPEAR. [74269.] Telephone System.Described fully on pp. 154 et seq. of Mr. Allsop's "Telephones." H. BROCKLEHURST. [74303.]-Galvanometer.-As Mr. Allsop does not appear to have noticed this query, I take the liberty of calculating the quantity. No. 34 wire has a resistance of 22 ohms per ounce.

No. 36

advantage than a share from 1 to 10, for,
besides four-fifths of the chance of the third
bag, they have nine-tenths of the chance of
There
bag.
tions, to which I will refer later on. The question
excep-
is not so much that any individual share, such as
432, which you name, has an advantage over 32 or
2, as that nearly every share numbered from 100 to
499 has a better chance of being drawn than any
share from 11 to 99, and a still better chance than
any share from 1 to 10. Stated as follows:

56.5 ohms per ounce. Therefore if 44oz. of it would appear that the chances were equal for No. 34 be required to give the necessary resistance each number; but, really, share 2 has but 1 in 5 of

[74560.]-Drawing Prism.-Will this querist Does he mean the explain what he means? arrangement of mirrors in the form of a kaleidoVIDEO scope sometimes used by designers?

[74565.]—Raising Water. - Better use all metal piping for raising water from a well. If valve is fitted at 26ft., the water will rise to that level; but it must there be emptied into a cistern, so that the atmospheric pressure can force it up the other. One pump-rod working through glands will do. What is the object of the deal rod?

[74570.]-Free Acid in Varnish.-Put some quicklime into the varnishes, shake, and allow them to settle; then decant. Can test for acid by means of litmus paper: it turns red if acid is present; or spoonful of the varnish. can be tested by a pinch of carbonate of soda in a PAINTER

[74571.]-Gas and Electricity.-About the same quantity of gas is required to work a gas engine to drive a dynamo to give so much light as would be required to give same amount of illuminstion if burned in good apparatus.