lockhead, a practical engineer, a small engine and a boat were constructed and fitted up: and in October, 1788, this boat was launched on the Loch of Dalswinton, in Dumfriesshire, and she attained a speed of five miles an hour. They then built a larger boat, the engine of which Mr. Symington constructed at Carron ironworks; and, in 1789, this vessel was launched on the Forth and Clyde Canal and propelled by steam, and she attained a speed of about seven miles an hour. These are among the earliest attempts of steam navigation of which we have authentic record. For some time after, this new enterprise lingered; but in the very beginning of the present century Mr. Symington's experiment was repeated on the Thames with complete success. While in America on the river Hudson, Mr. Robert Fulton, the son of a Scotsman who emigrated from Dumfriesshire, started a steamboat with an engine of Boulton and Watt, in 1807. It is a curious fact that, in the year 1814, Scotland had five steam vessels, while England had not a single one. In the following year, however, England had three, and in 1820, she had seventeen; while Scotland had fourteen. Subsequently, owing to causes easily understood, steam ships increased in number far more rapidly in England than in Scotland, though not faster in proportion to the population and wealth of the latter country.

The most striking and important of the improvements in steam vessels which have been made in the present century is the substitution of the screw-propeller for the paddle-wheels; while in the construction of ships themselves wood has been superseded by iron and steel.

With regard to the importance, the variety, the subtilty, and the power of its practical applications, and the latent or as yet undeveloped power inherent in it, the science of electricity takes a high rank; and with a brief and consequently a very imperfect notice of it in these various relations, this chapter will conclude.

The science of electricity is of modern growth; very little was known of its nature or powers prior to the last century, though some of its phenomena attracted the attention of a few scientific men in the seventeenth century. Between the years 1720 and 1736, Stephen Grey, assisted by Wheeler, discovered that the human body conducts electricity, that it acts at a distance-motion in light bodies being produced by frictional electricity at a distance of 666 feet; he also stated the fact of electric induction and other phenomena. About 1733, Dufay originated his dual theory of two electric fluids; and stated that two bodies similarly electrified repel each other, and

attract bodies oppositely electrified. What was termed the Leyden Jar was discovered by several persons in 1745; and the following year Winckler constructed the Leyden Battery. About the same time, important researches were made by Watson, Canton, and others. In 1747, Franklin enounced his theory of a single fluid; he termed the vitreous electricity positive, and the resinous negative; and, in 1752, he demonstrated the identity of the electric spark and lightning, drawing electricity from a cloud by the use of a kite. Still this subtle and powerful element was then but little understood; and, in 1752, Professor Richmann was killed at St. Petersburg while repeating Franklin's experiments. Since this period the subject has been treated continuously by many able and famous men of science.

The term electricity, as now applied, includes various phenomena of very different characters; such as magnetism, frictional electricity, and voltaic electricity. Two general properties may be noted—(1) polarity and (2) current action. In the first there is a uniformity through all its modes, and it is the pervading attribute which gives a distinctive character to all the phenomena: the second peculiarity of the electric forces is that they can be carried to any distance through solid conductors, so as to discharge themselves at any point. Frictional electricity is generated by mechanical force in electrical

machines.

The practical applications of the electric forces are now numerous, and all of comparatively recent introduction. Although the idea of applying electricity to communicate signals was conceived by Watson about the middle of the last century, the earliest proposal of this appeared in the Scots Magazine for February, 1753, when a correspondent from Renfrew, who signed himself C. M., proposed several kinds of telegraphs, acting by the attractive force of electricity, conveyed by a series of parallel wires equal in numbers to the letters of the alphabet, and insulated by supports of glass or jeweller's cement at every twenty yards. Words were to be spelt by the electricity attracting letters, or by striking bells corresponding to letters. Towards the latter part of the last century and the early part of this various plans of telegraphs were proposed by different men ; but 1837 is the date of the practical realisation of the electric telegraph. A few years later it began to be employed in connection with the working of railways; and it is obvious that the railway system could not have been developed without the aid of the electric tele

graph, or some similar method of rapid and instantaneous signalling. The modes of electric telegraph have been much perfected, and the systems of communication immensely developed, within recent years.

Among those who have advanced the knowledge of electricity and the development of its practical application during the past half century, the veteran Professor of Natural Philosophy in the University of Glasgow, Lord Kelvin, holds a distinguished place. He has made many experiments, practical applications, and written much on the subject.

Submarine electric telegraphs were successfully introduced in 1851, when the first line between Dover and Calais was opened; and it has since been greatly developed, and direct telegraphic communication established between Europe and America many years ago. Electric clocks were introduced in 1854, and are now common.

An apparatus for regulating the electric light was first devised and exhibited by Staite and Petrie in 1848. Jules Duboscq's electric lamp was shown at the Paris exhibition in 1855; and, in 1856, it was employed by Professor Tyndall for illustrating his lectures on light and colour, which he delivered that year at the Royal Institution in London. Since, the electric light has been greatly developed, and used for lighting public buildings, places of business, and the streets of cities; and if the cost of its production was reduced it would be more universally used for lighting purposes.

In 1854, M. Bonelli, of Turin, invented a plan of employing magnets and electro-magnets in weaving, by which he proposed to supersede the tedious and costly Jacquard system of cards. His loom was set up in London in 1859; and, in the summer of 1860, Professor Faraday lectured upon it at the Royal Institution. There are other applications of electricity which it is unnecessary to

enumerate.

An exceedingly useful and beautiful application has recently been made in the science of acoustics, by the invention of the telephone, which transmits the sounds of spoken language along wires to a considerable distance.

In concluding this chapter, the importance of mathematical science was indicated, and the Scotch mathematicians noticed; Dr. Black's researches and discovery of latent heat, and Leslie's treatment of radiant heat and experiments were explained; I then indicated the results of more recent researches and referred to spectrum analysis. The writings, experiments, observations, and the discoveries of Sir David Brewster were noticed; and the contributions of several

Scotsmen to geology were noted. The department of mechanical or applied science was then treated, and the writings of Dr. Robison and his teaching in this relation were noticed, and the bearing of the discovery of latent heat on the application of steam-power. A short account of Watt's career was given; his experiments on steam, improvements on the steam-engine, his struggles, and ultimate success, his genius, accomplishments, and character, were noticed. The early attempts of steam navigation were explained; and finally some account was presented of the discovery and the varied applications of electricity.

CHAPTER XLV.

Progress of Medical Science in Scotland in the Eighteenth and Nineteenth Centuries.

THE aim of this chapter is like the last one, not an attempt to present a history of the great and important science of medicine in all its branches, but to indicate what Scotland has contributed to the progress of this science, and also to give some account of the rise, the progress, and the organisation of the several institutions in which this science was taught in our country-in other words, the medical schools of Scotland. It will therefore, in the first place, indicate the bases of medical science; in the second, touch briefly on the prevailing theory in the early part of the eighteenth century; and in the third, proceed to narrate the advance of medical science in Scotland, and the establishment of our several medical schools.

The prime phenomenon presented to medical science is life. The first requisite of this science, therefore, is to enounce what life consists of, and more particularly what constitutes human life.-(1) As to the constituent elements of the human organism; (2) with reference to its structure; and (3) its functions. In other words, the science of medicine must be founded on biology; and it rests immediately on that part of biology termed human anatomy, physiology, and pathology-based on physiological analysis; and its subsidiary sciences are chemistry, botany, and some parts of physical science. The development of biology is gradually leading to a more scientific basis in the science of medicine, and the necessary conditions of health are becoming better understood.

Without entering into many details I shall endeavour to present the chief features of the prevailing theory in medicine immediately preceding the time when the Scottish schools began to arise; such a sketch is interesting in itself, and it will enable us to understand what Scotland has done in this great department of science.

Galen, born A.D. 131, was the oracle in medical science for upwards of 1400 years; but, in 1492, Paracelsus was born. The son of a physician, he determined to follow the profession of his father.