350 Dr. Maaieven on the Atomic Theory. [Nov. 



Or, if salts having the same acid and the same quantity be 

 required, the following will be found on the scale, viz. 46*5 sub- 

 carbonate of ammonia ; 75*5 bicarbonate of ammonia, 60 carbon- 

 ate of lime ; 118"8 carbonate of barytes, &c. Moreover, it will 

 be seen on the scale by looking at soda, that all the first named 

 salts contain 37 soda, and all the last named 26-2 carbonic acid. 



It is not always necessary to place the shder at 100. For any 

 acid, as 50 sulphuric acid, move the slider until sulphuric acid 

 on the scale stands opposite 50 on the slider, and the numbers 

 opposite the constituents of the acid, marked on the scale, will 

 give their proportional ^veights in 50 of the acid ; according to 

 this the oxygen will be 30, and the sulphur 20. 



For any salt, as 60 carbonate of lime, when 60 stands opposite 

 the carbonate of lime, the constituents will be 26-3 acid + 33*7 

 base. If the slider had been placed at 100 carbonate of Hme in 

 the usual way, the acid would be 43, and the base 56, but these 

 numbers for 100 are in precisely the same proportion as the for- 

 mer for 60. 



I shall conclude this view of the valuable scale of chemical 

 equivalents bv an example taken from Dr. Wollaston's paper, in 

 the Phil. Trans, for 1814, Part I. 



" In the second figure, the slider is represented drawn upwards 

 till 100 corresponds to muriate of soda ; and accordingly the 

 scale then shows how much of each substance contained in the 

 table is equivalent to 100 of common salt. It shows, with regard 

 to the different views of the analysis of this salt, that it contains 

 46*5 dry muriatic acid, and 53*4 of soda, or 39'8 sodium, and 

 13*6 oxygen ; or if viewed as chloride of sodium, that it contains 

 60'2 chlorine, and 39*8 sodium. With respect to reagents, it 

 may be seen that 283 nitrate of lead, containing 191 of litharge 

 employed to separate the muriatic acid, would yield a precipi- 

 tate of 237 muriate of lead, and that there would then remain in 

 solution nearly 146 nitrate of soda. It may at the same time be 

 seen, that the acid in this quantity of salt would serve to make 

 232 corrosive sublimate, containing 185*5 red oxide of mercury; 

 or would make 9 1 '5 muriate of ammonia, composed of 62 muriatic 

 gas (or hydromuriatic acid) and 29"5 ammonia. The scale shows 

 also, that for the purpose of obtaining the whole of the acid in 

 distillation, the quantity of oil of vitriol required is nearly 84, and 

 that the residuum of this distillation would be 122 dry sulphate 

 of ?oda, from which might be obtained, by crystallization, 277 

 of Glauber salt containing 1.55 water of crystallization. These 

 and many more such answers appear at once by bare inspection, 

 as soon as the weight of any substance intended for examination 

 is made by motion of the slider correctly to correspond with its 

 place in the adjacent column." 



