193 



On the Application of Liquids formed by the Condensation of Gases as 

 Mechanical Agents. By Sir Humphry Davy, Bart. P.R.S. Read 

 April 17, 1823. [Phil. Trans. 1823, p. 199.] 



The elasticity of vapours, in contact with the liquids from which 

 they are produced under high pressures in high temperatures, is 

 known to increase in a higher ratio than the arithmetical one of the 

 temperature ; but the exact law is not determined, and the loss of 

 latent heat in compression, and the re-absorption in expansion, 

 renders the advantage of steam under great pressure and at very 

 high temperatures doubtful in an economical view. No such doubt, 

 however, exists in regard to those fluids which require very great 

 compression for their existence, and where common temperatures are 

 sufficient to produce an immense elastic force. Thus sulphuretted 

 hydrogen, which condenses into a liquid under a pressure of 14 at- 

 mospheres at 3, had its elastic force increased so as to equal a 

 pressure of 17 atmospheres by raising its temperature to 47. Liquid 

 muriatic acid at 3 exerted an elastic force equal to the pressure of 

 20 atmospheres, at 25 =s 25 atmospheres, and at 51 = 45 atmo- 

 spheres. 



After some experimental illustrations of the expansibility of the 

 vapour of sulphuret of carbon at different temperatures, the author 

 adverts to the possible application of the difficultly compressible 

 gases, as mechanical agents, and to their power of producing cold 

 by the rapidity of their evaporation. 



On the Temperature at considerable Depths of the Caribbean Sea. By 

 Captain Edward Sabine, F.R.S. In a Letter addressed to Sir 

 Humphry Davy, Bart. P.R.S. Read April 17, 1823. [Phil. 

 Trans. 1823, p. 206.] 



In this letter Captain Sabine details the results of some experi- 

 ments on the temperature of the Caribbean Sea, in lat. 20 N. and 

 long. 83^ W. At the depth of 1230 fathoms by the line, or about 

 1000 fathoms actual depth, a six's register thermometer indicated 

 45- 5, the temperature of the water at the surface varying from 

 82-5 to 83'2, so that the difference amounted to 37'3. 



Letter from Captain Basil Hall, R.N. to Captain Kater, communica- 

 ting the Details of Experiments made by him and Mr. Henry Foster, 

 with an Invariable Pendulum, in London ; at the Galapagos Islands 

 in the Pacific Ocean, near the Equator ; at San Bias de California 



1 on theN.W. Coast of Mexico; and at Rio de Janeiro in Brazil. 

 With an Appendix, containing the Second Series of Experiments in 

 London, on the Return. Read April 24, 1823. [Phil. Trans. 

 1823, p. 211.] 



Captain Hall stated that the ship which he commanded had been 

 constantly employed on a particular description of service, having no 

 reference to such inquiries, but which occupied nearly all his time. 



VOL. II. O 



