Jan. 19.-PROFESSOR DEWAR-Scientific Uses of Liquid Air March 2.-PROFESSOR JOHN G. MCKENDRICK-The Theory of 1894. May 7.-General Monthly Meeting 25.-SIR COLIN SCOTT-MONCRIEFF-The Nile 22.-PROFESSOR A. SCHUSTER-Atmospheric Electricity 460 March 8.-PROFESSOR A. W. RÜCKER-The Physical Work 22.-SIR WEMYSS REID-Emily Brontë (no Abstract).. 521 29.-PROFESSOR H. E. ARMSTRONG-The Structure of. Moon during the progress of an Eclipse 7.-PROFESSOR ALFRED CORNU-Phénomènes Physiques des Hautes Régions de l'Atmosphère July 1-General Monthly Meeting Nov. 4.-General Monthly Meeting Royal Institution of Great Britain. 6 APR 948 WEEKLY EVENING MEETING, Friday, January 20, 1893, SIR FREDERICK BRAMWELL, Bart. D.C.L. LL.D. F.R.S. Honorary Secretary and Vice-President, in the Chair. PROFESSOR DEWAR, M.A. LL.D. F.R.S. M.R.I. Liquid Atmospheric Air. The THE prosecution of research at temperatures approaching the zero of absolute temperature is attended with difficulties and dangers of no ordinary kind. Having no recorded experience to guide us in conducting such investigations, the best instruments and methods of working have to be discovered. The necessity of devising some new kind of vessel for storing and manipulating exceedingly volatile fluids like liquid oxygen and liquid air, became apparent when the optical properties of the bodies came under examination. liquids, being in active ebullition, were in a condition which rendered optical measurements impossible. All attempts at improvement on the principle of using a succession of surrounding glass vessels, the annular space between such vessels having the cool current of the vapour coming from the boiling liquid led through them, proved a failure. Apart altogether from the rapid ebullition interfering with experimental work, the fact that it took place involved a great additional cost in the conduct of experiments on the properties of matter under such exceptional conditions of temperature. While suffering great anxiety on the question of expenditure, the Goldsmiths' Company came forward with the handsome contribution of 1000l. to continue the work with improved apparatus. Personally, I desire to express my grateful thanks to the Goldsmiths' Company for tendering such encouragement and support. On careful consideration it became apparent that the proper way of attacking the problem was to conduct a series of experiments on the relative amounts of heat conveyed to boiling liquid gases; firstly, by means of the convective transference of heat by the gas particles, and, secondly, by radiation from surrounding bodies. The early experiments of Dulong and Petit on the laws of radiation had proved the very important part played by the gas particles surrounding a body in dissipating heat otherwise than by pure radiation. In the year 1873 I used a highly-exhausted vessel in calorimetric experiments" On the Physical Constants of Hydrogenium" (Trans. VOL. XIV. (No. 87.) B |