126 Analysis of Scientific Books. 
plication of the elastic force of compressed gases to the movement 
of machines. He founds this anticipation upon the immense dif- 
ferences between the increase of elastic force in gases under high 
and low temperatures, by similar increments of temperature. The 
force of caaboni¢ acid was fouud to be equal to that of air com- 
pressed to 3/5 at 12°, and of air compressed, to z/; at 32°, making 
an increase equal to the weight of thirteen atmospheres, by an in- 
crease of 20° of temperature. 
7. On the Temperature at considerable depths of the Caribbean Seu. 
By Captain Edward Sabine, F.R.S. 
[In a Letter addressed to Sir H. Davy, Bart., P.R.S.] 
Captain Sabine found the temperature of the water, at a depth 
of 6000 feet, in latitude 204 N. and long. 83} W. near the junction 
of the Mexico and Caribbean Seas, to be 45° .5, that of the sur- 
face being 83°. He infers, that one or two hundred fathoms more 
line, would have caused the thermometer to descend into water at 
its maximum of density as depends on heat; this inference being 
on the presumption that the greatest density of salt water occurs, 
as is the case in fresh water, ‘at several degrees above its pein] 
point. 
8. Letter from Captain Basil Hall, R.N., ¢o Captain Kater, commu- 
nicating the details of Experiments made by him and Mr. Henry 
Foster, with an Invariable Pendulum; in London; at the Gala~ 
pagos [slands in the Pacific Ocean, near the Equator ; 3 at San 
Blas de California on the N.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. 
The title is an abstract of the paper, and the follewing are the 
most exact results obtained by Captain Hall at each station. 
Diminution uf Gravity ee 
From Poleto Equatos,| Ellipticity, 
Length of Equat. 
Stations, Pend. 
Galapagos, 632 " NI .0051412 39.017196 
San Blas, 21 30 . 0054611 39. 00904 
Rio;.... 3 22°55 0053431 3901206 
