24^ °1* SALTS. 



— nor on the pc- the bafes themfelves do not throw more light on the pheno- 

 thelnTeiient^ mena °^ de l'queicence than their proportions; for there arc 

 themfcltes. deliquefcent falts,, the component parts of which taken fepa- 

 rately, have not any remarkable .attraction for water, fuch is 

 the nitrate of alumine; while on the other hand the fulphate 

 of foda is efflorescent, although concentrated fulphuric acid, 

 and cauftic foda each feparately attract humidity. Nothing 

 better proves this axiom in chemi ftry, —Compounds have pro- 

 perties peculiar to themfelves, and differing from thofe of their 

 component parts. 

 Generally the In general deliquefcent falts encreafe their weight in a di- 



dehquefcence nri n jfhi n g proportion, according as they approach faturation; 

 when the fatu- thus the acetate of polafh, which in the hrft twenty days ex- 

 «tion was leaft. hibited the following progreffion: 21. 34. 44. 54. 60. 70. S5. 

 100. 110. 120. 128. 138. 142. 148. 160. 169. 177. 186. 192. 

 198. did not (hew on the laft twenty days more than this, 647. 

 650. 655. 660. 663. 666. 669. 671. 676. 682. 684. 686. 688. 

 690. 692. 694. 696. 698. 699. 670. The falts which were but 

 little deliquefcent preferred a lingular phenomenon, which 

 none, I believe, has obferved before. 

 Remarkable The acid fulphate of alumine, and the acid phofphate of 



facts s falts lj m e, increafed and diminimed fucceffively in weight. 



which lofe part ' . ,,-.,, r 



cf the abforbed The muriate ot copper diminiQied during 45 days before it 



water and after- began to encreafe. Thefe ofcillations and retrograde move- 

 more and en- ments take place but once, arid when the fait has abforbed a 

 creafe till fatu- certain quantity of water, there is a progreffive increafe, al- 

 though flowly, until its perfect faturation, which may depend 

 on the attraction of water for water, an attraction which is not 

 perceptible but in certain proportions. 

 Expediency of Thefe anomalies deferve to be obferved again, and corn- 

 further experi- pared with experiments made on other falts which do not ex- 

 hibit them. They tend to make -us acquainted with all the 

 caufes that produce efHorefcence and deliquefcence, fince they 

 prefent each phenomenon fuccefiively. The falts which we 

 fubmitted to their action, had certainly an attraction for water 

 * very little different from that of air in a medium iiate cf heat 



and humidity. The point of equilibrium muft be decided by 

 the ftate of the a'mofpliere, or A the falts would remain un- 

 altered. 

 Thefe will pro- I ftill however think that a relation exifts between the me- 

 bably fhew that t eoro lc£ical variations and the alterations of the falts; and if I 



•mcrpnric vana- ° 



meteoric vana 



tions in the air .» '. was 



