49 



the manufacture of Sulphuric Acid is to make the oxygen of 

 the atmosphere combine with sulphur in the presence of suffi- 

 cient water to give it the required strength. 



If sulphur be burnt in the open air, it combines with two- 

 thirds of the oxygen necessary to make Sulphuric Acid, and is 

 called Sulphurous Acid ; the last third cannot be made to com- 

 bine directly from the atmosphere, and so means have been de- 

 vised by which it may be made to do indirectly ; these are the 

 introduction of Nitric Acid vapor into a mixture of Sulphurous 

 Acid and atmospheric air and steam ; the Nitric Acid parts 

 with some of its oxygen to the Sulphurous Acid, which, becom- 

 ing Sulphuric Acid, dissolves in the steam and falls as a rain, 

 while ttye Nitric Acid takes ba.ck from the atmosphere the 

 oxygen which it had lost, to give it again to another portion of 

 Sulphurious Acid, thus acting as a carrier of oxygen between 

 the two. 



All these conditions are ensured in the construction and man- 

 agement of the Sulphuric Acid " chambers," as they are called. 

 These chambers are vast rooms, whose sides, top and bottom, 

 are composed of sheet lead, and all along on the outside run 

 steam pipes for the admission of steam into the interior; ante- 

 terior to the chambers is the furnace in which the sulphur is 

 burnt and the Nitric Acid evolved. 



This Company has two sets of chambers, of an aggregate 

 capacity of 180,000 cubic feet, and their consumption ot sulphur 

 per day of twenty-four hours is 7,200 Ibs. The set last erected 

 contains the largest single chamber in the United States, having 

 the following dimensions: 140 feet x 30 x 25 ; while the furnace 

 of cast-iron is the only one in America, and the largest in the 

 world. They have also attached to their chambers the con- 

 densers of Gay Lussac, thus reducing their consumption of 

 Nitre from 10 per cent, to 4 per cent., and their production is 

 from 280 to 285 Ibs. of Monohydrated Sulphuric Acid to the 

 hundred pounds of sulphur consumed. 



Drying and Grinding. The rock, as it comes from the washers 

 of the miners is loaded on sloops, schooners and flats, and trans- 

 ported to the wharf of the Company, where it is discharged by 

 a derrick, which is driven by a wire rope 320 feet from the en- 

 gines. A shed 200 feet long, paved with brick and supported 

 by iron pillars, extends backwards from the wharf. On this 

 brick pavement is laid two rows of pine wood ; overhead is a 

 railroad, on which* run the cars into which the rock is dis- 

 charged, and from which it is dumped upon the wood beneath. 

 When the cargo has been thus discharged, the wood is set fire 

 to and the '" kiln " burns and is dried; by the well considered 

 arrangements of this Company, tho consumption of wood is 

 reduced to one cord of wood to forty tons of rock, thus obvi- 

 ating some of the damage done by too much heat, while the 

 rock is still thoroughly dried. 

 4 



