1813.] Definite Proportions in Chemical Coriihinat ions. Ill 



Number of Weight of an 



atoms. integrant particle. 



h 



117. Cubic pyrites 1 i + 4 s 14-666 



118. Sulphuret of nickel 1 n + 1 s 5*623 * 



119. Prosulphuret of tin 1 t + 1 s 16*705*- 



120. Perstilphuret of tin or? j ; , , ^ ,.18*705 

 mosaic cold 3 



121. Sulphuret of lead 1 I + 2 s 29*974 ! 



122. Persulphuret of lead .... 1 I + 4 s 33*974 " 



123. Sulplmret of zinc 1 z + Is 6-315 n 



124. Sulpliuret of bismuth . . 1 b + 1 s 10*994° 



■' From Berzelius' experiments (Ann. de Chim. lxxviii. 130), 

 it appears tbat the quantity of sulphur in cubic pyrites, supposing 

 the iron the same, is just double what exists in magnetic pyrites. 

 Hence cubic pyrites must be a compound of 1 atom iron and 4 

 atoms sulphur. 



' According to Proust, 100 nickel combine with 48 sulphur. 

 Now 100 : 48 :: 3*623 : 1 739. This, considering the uncer- 

 tainty respecting the weight of an atom of nickel itself, is not a 

 greater deviation from the weight of an atom of sulphur than 

 might have been expected. If the weight of an atom of nickel 

 given in my table be correct, then 100 nickel ought to combine 

 with 55*2 sulpha*. 



** From the experiments of Mr. John Davy (Phil. Trans. 

 1812), it appears that the common sulphuret of tin is composed 

 of 55 tin + 15 sulphur. Now 55 : 15 :: 14*705 : 4*015; but 

 4*015 is almost exactly the weight of 2 atoms of sulphur. From 

 Mr. John Davy's experiments, it appears that mosaic gold con- 

 tains just double the sulphur in common sulphuret. 



1 From the analysis of Berzelius, we learn that galena is 

 composed of 100 lead + 15*42 sulphur. (Larbok i Kemien, ii. 

 2/6.) Now 100 : 1542 :: 25*974 : 4*005 j but 4*005 is almost 

 exactly the weight of 2 atoms of sulphur. The analysis of Mr. 

 John Davy differs very little from that of Berzelius. 



"* Some years ago 'I received a specimen of galena from Sir 

 John Sinclair, which contained twice the usual quantity of sul- 

 phur. Hence it is obvious that a persulphuret of lead exists. 



" From the experiments of (.iueiiivcau and Kidtl, it appears 

 that blende consi*ts of 1<)<) zinc + 49 sulphur. Now 100 : 49 

 :: 4*315 : -2*11-1 ; but 2*114 does not differ much from the 

 weight Of an atom of sulphur. As sulphuret of 21 lie has not yet 

 been made artificially, and as blende contain, iron, we cannot 

 expect our analysis to come nearer the truth. 



" According to M. .John Daw, 67*5 bismuth unite with 

 15*08 of sulphur. Now c;7* r > *. 15*08 :: B-9W : 2-009. But 



