472 Intelligence and Miscellaneous Articles. 



To investigate the influence of the quantity of the absorbed gases 

 on the magnitude of the change in the melting-point, the tempera- 

 ture of a mixture of ice and water which was saturated under 1 , 2, 

 3 atmospheres was examined, and was found to be — 0°T3, — o, 25, 

 and — o, 35. The alteration in the melting-point seems proportional 

 to the amount of dissolved gas. 



The remarkable property which ice has of regelation has been 

 variously interpreted. Faraday has explained it by assuming that 

 the particles in the interior of a mass of ice have a higher melt- 

 ing-point than those on the surface*. Forbesf and others assume 

 that ice on melting assumes an intermediate condition of softness, 

 and that in this condition pieces adhere together, like those of weld- 

 able metals. Thomson % and, subsequently, Helmholtz explain the 

 phenomenon by an alteration in the melting-point of ice by 

 pressure. There must always be an increase in pressure on inti- 

 mate contact of the pieces of ice ; under this pressure a portion of 

 the ice must melt at the surface of contact, the water formed must 

 run off, and, in virtue of its lower temperature, partially freeze again 

 in places where it is liberated from pressure. 



If in regelation a fresh formation of ice from water be as- 

 sumed, the action of the air on the melting-point must influence the 

 process of regelation. Pure ice can only retain a temperature of 0° 

 in pure water ; when it slowly thaws in air, or in water containing 

 air, its temperature is lower ; a layer of pure water, or of water which 

 is not saturated with air, can therefore freeze between two pieces of 

 such ice. This condition must in many cases be considered to exist. 



Hence in an atmosphere of carbonic acid the phenomenon of 

 regelation must be more decided than in common air ; the experi- 

 ment, in fact, frequently succeeds. Yet the rapidity with which 

 water becomes saturated with carbonic acid seems to exert a disturb- 

 ing influence ; for probably the water between the surfaces in con- 

 tact is also quickly saturated with carbonic^ acid. — Poggendorff's 

 Annalen, No. 6, 1869. 



DISTURBANCES OF RESPIRATION, CIRCULATION, AND OF THE 

 PRODUCTION OF HEAT AT GREAT HEIGHTS ON MONT BLANC. 

 BY M. LORTET. 



On the 17th and 26th of August, 1869, I made two ascents of the 

 highest peak of Mont Blanc. In the interval I twice passed the Col 

 du Geant; and before returning to Lyons I traversed other high 

 passes, and ascended several secondary summits in order to verify 

 the results I had obtained in reference to the disturbance which re- 

 maining or moving at great heights may produce in various physio- 

 logical functions. The instruments which I used for estimating these 

 are the anapnograph of Bergeon and Kastus, Marey's sphygmograph, 



* Proc. Roy. Soc. vol. x. p. 440. 

 t Phil. Mag. S. 4. vol. xvi. p. 544. 

 X Proc. Roy. Soc. vol. ix. p. 141. 



