62 



Art. VII. 071 Anhydrous Sulphuric Acid* By Andrew 



Ure, M.D., F.R.S., 8^c. 

 Dear Sir, 



Several years ago I procured from a friend at Ham- 

 burgh a bottle of the oil of vitriol of Nordhausen, intending 

 at that time to examine its constitution, and to give you an ac- 

 count of it, in supplement to my paper on sulphuric acid, inserted 

 in the 7th number of your Journal. This bottle was by accident 

 overlooked by me till lately, when I made the following experi- 

 ments on its contents. 



A portion of this brownish-coloured oil of vitriol, sp. grav. 

 1.842, was distilled slowly from a glass retort, intt) a globulaf 

 glass receiver, surrounded with ice. A white sublimate soon ap- 

 peared in the globe and beak of the retort. When this sublimate 

 was exposed to the air, it emitted a profusion of dense fumes of 

 sulphuric (not sulphurous) acid. It burned holes in paper, with 

 the rapidity of a red hot iron. 



A phial, containing 988 grains of distilled water, which occit» 

 pied two-thirds of its capacity, was poised in a sensible balance. 

 Into this water a piece of the acid sublimate, of a tallowy consis- 

 tence, slightly deliquesced on the surface, was dropped, and the 

 phial was suddenly closed with its stopper, to prevent the ejection 

 of liquid by the explosive ebullition which always ensues, when 

 this solid acid comes into contact with water. The increase of 

 weight due to the introduction of the acid into the phial, was found 

 to be 56 grains. The total weight and specific gravity of this 

 dilute acid were at G0° Fahr. 1043.6 grains, water being lOOOi 

 At this density, 1000 parts of sulphuric acid, of the common kind, 

 contain 53 parts of dry acid, equivalent to 65 of liquid acid, sp. 

 gr. 1.844. But in 1000 grains of the above dilute Nordhausen 

 acid, there was at the utmost only 53.6 grains of the sublimate, 

 which, considering the deliquescence on its surface, is a quantity 

 agreeing with the supposition of its being anhydrous acid. 



To put this point more fully at rest, I saturated 9S7 grains of 

 the above dilute acid with pure carbonate of potash, prepared from 



