VOL. LXXXII.] PHILOSOPHICAL TRANSACTIONS. 24g 



fore from either the acid or the alkali : it remains therefore that it arose from the 

 water. 



The weight of the calx of the zinc was ascertained by drying it after washing 

 out the vitriolated tartar, heating it to a red heat, and afterwards weighing it. 

 The weight of the zinc dissolved in saturating the acid, was l64grs. : the 

 weight of the calx 220 grs. The additional weight was therefore 56 grs. 



If it arose from the water, then a quantity of water, equal to the weight by 

 which the calx exceeds the metal, must be lost in the operation. To determine 

 this, I performed a distillation in the following manner. I put 1000 grs. of the 

 same diluted vitriolic acid into the globe a of the same apparatus, then intro- 

 duced the quantity of aqua kali puri found necessary to saturate it. The tube d 

 was then bent downwards about the middle, and the apparatus brought to an 

 horizontal position ; so that the bent part of the tube was in a perpendicular 

 direction downwards : to this I affixed a small phial, and weighed the whole. I 

 then put the globe b in a box filled with ice, and applied heat to the globe a, so 

 as to distil over the water into the globe b, the liquor never being brought to the 

 boiling point. When the matter in the globe a became dry, the heat was increased 

 to a red one, to distil over also the water of crystallization. The whole apparatus 

 was now weighed, and found not to have lost a grain ; nor was there any water 

 in the phial. I then cracked the tube c, by applying a red-hot iron to it, and 

 letting a drop of cold water fall on it. I next weighed the globe b with the water 

 in it, then poured out the water, and let the glass dry. I weighed the glass ; 

 the deficient weight from the former weighing, being the weight of the water, 

 was lOOgS grs. 



I repeated the experiment, with this difference ; I put 1000 grs. of the same 

 vitriolic acid into the globe a, then introduced the quantity of zinc sufficient to 

 saturate it : I took the weight of the inflammable air as before, and found it 

 nearly the same in weight and quality. The same quantity of aqua kali puri 

 was then introduced through a funnel as in the former experiment, then the 

 tube was bent downwards, and a phial applied to it as before. The whole appa- 

 ratus was weighed after the distillation, and found not to have lost any sensible 

 quantity of weight, nor was there any water in the phial. The phial being 

 detached, and the tube broken as before, the globe weighed again when dry, the 

 deficiency was less than in the former experiment by 63 grs., which is 2 grs. less 

 than the additional weight of the calx above the metal and of the inflammable 

 air taken together ; and therefore the matter occasioning the additional weight 

 of the calx above that of the metal, and the inflammable air, are both produced 

 from the water. 



XX. On the Civil Year of the Hindoos, and its Divisions; with an account of 



VOL. XVII. K K ^ 



