250 Dr Davy on the CombmaUons of 



carefully weighed in a balance, which is distinctly affected by 

 YTo of a grain, was introduced into a tube over mercury, contain- 

 ing ffo cubic inch of dilute muriatic acid. The gas disengaged 

 when the marble was quite dissolved, was 89 cubic inches, or, 

 allowing for absorption, by the acid, about .92. Now consider- 

 ing carbonate of lime as composed of 9.Q,B lime, and 20,7 car- 

 bonic acid; and 100 inches of the acid gas to weigh 47.469 

 grains, one grain of the marble ought to yield .927 cubic inch, 

 a difference not appreciable between the estimate and the result.* 

 Five grains of salammoniac, part of a translucent mass, pre- 

 cipitated by nitrate of silver, afforded 13 grains of chloride of 

 silver well washed, and perfectly dried, at a temperature above 

 212"^ \. Now, considering the proportion in which silver com- 

 bines to be 108, that of muriatic acid 36.45, and that of ammo- 

 nia 17, according to Dr Turners estimates of the equivalents 

 of silver, chlorine, and azote J ; and admitting that muriatic acid 

 gas and ammonia combine in equal volumes to form muriate 

 of ammonia, and that 100 cubic inches of ammonia weigh 

 18.3837 grs. at 60°, and 100 of muriatic acid gas 40.0121 grs. ; 

 it may be inferred from this result that Salammoniac is com- 

 posed of 



30.70 Ammonia ; 

 66.86 Muriatic Acid ; % 



or of 



17 Ammonia (1 proportion 17) 



37 Muriatic Acid (1 36.45.) 



an approximation this as great as might be expected be- 

 tween an experimental result and an estimate; and agreeing 

 exactly with another estimate, founded on the weight of the 



• The barometer and thermometer at the time, were close on 30° and 60*. 

 The power of saturation of the dihite acid was ascertained by experiment. 



' f The same result was obtained in three different experiments. 



X London and Edinburgh Philosophical Magazine and Journal, for Au- 

 gust 1832, p. 110. 



X The loss 2.46 grs. may be considered in part owing to hygrometrical 

 water, which, according to experiments, is .^ per cent. ; and, in part, to the 

 manipulations and the data for calculation derived from experiments. 



