• l8 Sfiui/ic Gravities of AUop of Tin mid Lead. 



TABLE of the Concfpondencies of the Specific Gravities of Alloys of Tin and Lead, 

 with the refpctlive Proportions of thefe Metals. 



In conftrudiiig this table, I have made ufe of the obfervations publiflied by M. Ber- 

 genilierna in the Memoirs of the Academy of Stocltholm for 1780, and reprinted in the 

 Manuel Syftematiquc of M. Gren (^ 3195)- But as he grounded all his ratios on the 

 variations of abfolute weight under equal volumes, and made ufe of foreign, weights, I 

 have been obliged to change the expreflion for the more fimplc and ufual proportion to 

 diftilled water, taken as unity. 



At every fifth line I have added the mathematical fpecific gravity, or that which is deter- 

 mined by calculation, in order to fhew the changes of bulk which refult from the combina- 

 tion, and in this particular cafe diminifli the denfity inftead of increafing it. 

 The fpecific gravity of pure lead to water is as 11. 1 603 to i. 

 The fpecific gravity of pure tin is 7.2914 to i. 



adding I, 1, J, &c. parts by weight of the fpirir, to the conftant quartity 100 of water. ( i ) The fpecific gravity 

 to five places of iigare*; (1) the proponioa of uiater by tncafoic to the fpirit taken as 100; (3) the aftual 

 bulk of this Ijft mixture ; (4) the dimintuion of bulk by mixture ; (5) the quaiitit) of fpirit per cent. ; and 

 (6) a decimal multiplier, which being applied to the bulk of the mixture gi\es the meafureof the pure fpirit in 

 a mixture of tliat denfity. Hence it may be inferred how extcnfivety ufeful this table muft prove to all practical 

 philofophcrs and manufaflurers. With regard to its accuracy, I mufl refer to the ample reports of Dr. (now Sir 

 Charles) Blagden, in the Tranfaflions for 1790, and fkall only obfcr^s that (he experiments were mad: with 

 the balance of the Prcfidcnt of the Royal Society ; of the admirable mcchaaiGn and fcnfibility of wliich, fome 

 account, though imperfc^, is given iathc Journal dc Rozier, Vol. XXXIll. and that the term or (landard fpirit 

 .Sz5 was arbitrarily chofcn from motives of convenience and accuracy. 



The fpirit was obtained from malt. The grealeft ftrength obtained by adding hot cauflic alkali to fpirit and 

 then carefully diftilling, gave a fpecific gravity of 0.813 at 60 degrees. Pcihaps the circumftances of M. Gou- 

 veDiii>-> expcrinicDn may llicw by what means he fuccecdcd in arriving at 0.7980 at the fame temperature. 

 No ufeful purpofe would be anfweced by coDJe£lure is this place. From the InA line in the table here given by 

 Ciiizea Goylon, tlic fpecific gravity of mete water is fuch as to indicate a temperature of 75 degrees inHead of 

 69 in ChAui&er's column. In which cafe Gilpin's, llandard fpirit would have a fpccihc gravity of 0.8178. 

 With ce^rd to the coafiderable diSereoce in the penetration or diminution of bulk, it remains to be (hewn 

 whether it depends upon any part of the procdTcs by which the .tlcobol was obtained and concentrated, or, as is 

 Rvjie probable, upin Umt rai-lakc in the calculations or methods of exprcUing the quantities. N. 



Compound 



