314 SPECIMENS or SIR J. HALL*S EXPEUIMENTS, 



Explanation^ 



Explanation of Column I. contains the ntmiber of the experiment, as refer-' 

 forcJsf&c"^ red to in the text. Column II. The bore of the barrel used, in 

 decimals of an inch. Column III. The absolute force applied 

 to the barrel, in hundred-weights. Column IV. The tempera- 

 ture, in WedgAvood's scale. Column V. The depth of sea 

 at which a force of compression would be exerted equal to that 

 sustained by the carbonate in each experiment, expressed in 

 feet. Column VI. The same in miles. Column VII. Com- 

 pressing force, expressed in atmospheres. 



Both Tables were computed separately, by a friend, Mr. J. 

 Jardine, and myself. 



The following data were employed : 



Area of a circle of which the diameter is unity, 0.785398. 



Weight of a cubic foot of distilled water, according to Pro- 

 fessor Robison, 998.74 ounces avoirdupois. 



Mean specific gravity of sea-water, according to Bladh, 

 1.0272. 



JNIean heighth of the barometer at the level of the sea 

 29.9119s English inches, according to Laplace. 



Specific gravity of mercury, according to Cavendish and 

 Brisson, 13.568. 



III. 



Catalogue of thirty-one Spechneus, shewing the Resvlt of Siik 

 James Hall'* Experiments on the Effects of Heat modi" 

 fed by Compression ; which were deposited by him in the 

 British Museum, on the 2Sth of June I8O6.* 



Specimens of J^ UMBERS 1, 2, 3, 4, 5, 6, and 7, were all produced in 



results of bodies separate experiments from pounded carbonate of lime. 



exposed to ^ * , . , . 



strong heat Number 1, was obtamed m 1799- It is a firm stone, requinng 



under compres- ^ smart blow of a hammer to break it. It was enclosed in a car- 



Pion, by Sir 



James Hali. tiidge of paper, the mark of which it still bears. The other six 



* Communicated to the editor by the author. 



