368 Dr. Henry^s Analysis of a crystallized Compound [May^ 



Article IX. 



Analysis of a crystallized Compound of Hypovitrous and Sul- 

 phuric Acids. By William Henry, MD. FRS. &c. 



(To the Editors of the Annals of Philosophy.) 



GENTLEMEN, Manchester, Jpril 12, 1826. 



About three months ago, I was indebted to Mr. Mutrie, an 

 extensive manufacturer of sulphuric acid and other chemical 

 products, at Lloyd-field, near Manchester, for the opportunity 

 of examining a substance, which was found in the leaden pipe 

 that conveys away the foul air from one of the chambers used 

 to condense the acid, formed by burning nitre and foreign sul- 

 phur in a separate vessel. The weather was at that time intensely 

 cold, and the product of acid had unaccountably fallen off to a 

 great extent. It was suspected, therefore, that the ventilating 

 pipe was closed with sublimed sulphur; but when examined 

 internally, it was found to have been completely stopped, at au 

 angle where from an horizontal it takes a perpendicular direc- 

 tion, by a crystalline solid not unlike borax in appearance. The 

 portion, which was brought to me, formed a soUd mass at the 

 bottom of a bottle, from which it could not be detached without 

 so much force as to destroy the shape of any crystals that 

 might have composed it. When kept for a day or two in a 

 warm room, it assumed a soft or pasty form ; and, by standing 

 still longer, a liquid of rather thick consistence, and of the spe- 

 cific gravity 1*831, floated over the more solid part. 



The crystalhne portion of the mass, from which the liquid had 

 been drained, but which still continued a soft solid, was intensely 

 acid to the taste, and, when handled, stained the fingers like 

 strong nitrous acid. When added to water, a rise of tempera- 

 ture of more than 60° F. was produced, and a violent efferves- 

 cence took place, accompanied with red fumes resembling those 

 of nitrous gas when escaping into the atmosphere. A similar 

 extrication of gas was observed, on pouring the deliquiated por- 

 tion of the mass into water. By dissolving a given weight of 

 the solid, in a gas bottle nearly filled with water, gas was 

 collected at the rate of 16"6 cubic inches from 100 grains. Of 

 this, which proved to be nitrous gas of remarkable purity, rather 

 more than one-half was evolved without applying heat, and the 

 remainder issued on heating the solution. 



When the crystalhne substance was heated alone in a small 

 glass bulb, the stem of which was bent so as to pass under the 

 surface of water in a pneumatic trough, it was found to sustain a 

 temperature of 220° F. for more than an hour without parting 

 with any gas ; but at 280°, nitrous gas was evolved. A tem- 



