Appendix.] MODIFIED by COMPRESSION. i8t 



The firfl eleven are the fame with thofe ufed in the paper read 

 in this Society on the 30th of Auguft 1804, and published in 

 Nicholson's Journal for October following, and which refer 

 to the fame fpecimens. No. 12. Is a fpecimen of yellow marble, 

 bearing a ftrong refemblance to No. 3. No. 13. A fpecimen of 

 chalk. No. 14. Shews the average of -three trials with chalk. 

 No. 15. Some pounded chalk, rammed in the manner followed 

 in thefe experiments. In order to afcertain its fpecific gravity, 

 I rammed the powder into a glafs-tube, previoufly weighed ; 

 then, after weighing the whole, I removed the chalk, and filled 

 the fame tube with water. I thus afcertained, in a direct man- 

 ner, the weight of the fubflance, as ftated in Column II., and 

 that of an equal bulk of water, ftated in Column VIII. 



Column II. Weight of the fubflance, dry in air, after expo- 

 fure, during feveral hours to a heat of 212 ° of Fahrenheit. 



Column III. Its weight in water, after lying long in the li- 

 quid, fo as to perform its full abforption ; and all air- bubbles 

 being carefully removed, 



Column IV. Weight in air, wet. The loofe external moift- 

 ure being removed by the touch of a dry cloth ', but no time 

 being allowed for evaporation. 



Column V. Difference between Columns II. and III., or ap- 

 parent weight of water difplaced. 



Column VI. Difference between Columns II. and IV., or the 

 abforption 



Column VII. Abforption reduced to a per cent age of the dry 

 fubflance. 



Column VIII. Sum of Columns V. and VI., or the real 

 weight of water difplaced by the body. 



Column IX. Specific gravity, by the common mode, refult- 

 ing from the divifion of Column II. by Column V. 



Column X. Specific gravity, in the new mode, refulting 

 from the divifion of Column II. by Column VIII. 



The 



