Mining Induat~,y in F~anee. 31 Now, whereas, we do not claim as our invention, or as any part the~ef, any particular apparatus for generating carbonic acid gas, nor the partie(/lur metes hereinbefore described, of introducing the same, when generated, in, to our solution, although we have shews the best which we are at present acquainted with, for the purpose of obtaining those two objects; nor do we elmm as our invention, or as any part thereof, any particular apparatus as necessary to be

more »

... in order to obtain either the combustion or purifies, tion, aforesaid, of the vapours and gases arising from the fuel in the furJ~tce. But we claim as our invention, first, the acting upon the vapours'and gases arising from the fuel used in the furnace employed in the pt;ocess of making white lead, in such manner (by burning and by washing the said vapoers and gases in manner hereinbefore described,) whereby we destroy the impurities in the said vapours and gases which are injurious to the eolour and qualiiy of white lead, and are enabled to use that cheap kind of fuel, called anthracite, or stone coal, or mineral coal, or coke, in the said furnace~ in. stead of charcoal, and also to use the carbonic acid gas obtained therefrom in the process of manufacturing white lead. Secondly, the manufacturing white lead from compounds of nitric acid with oxide of lead, in which lhe quantity of oxide of lead bears a greater ratio to the nitric acid combined therewith, than the oxide of lead bears to the nitric acid in the ordinary nitrate of lead of commerce, and which nitrates we call, and are known by the name ot~ basic nitrates of lead, in the manner hereinbefore described; and Thirdly, the making of white lead by unitin~ and acting upon, or mixing, litharge, massicott, or protoxide of lead, with nitrate of lead, (which uniting, and acting upon, or mixing, are best eft'erred by boiling, as hereinbefore described, but may be obtained at less degree of temperature, though not so advantageously, without boiling,) and submitting the same, so mixed together, to the action of, or bringing the same, so mixed together, minutely into contact with, carbonic acid, in order to produce carbonate of lead, or, as it is usually called, white lead, and in such manner that the same nitrate of lead may be used over and over again many times, with fresh portions of litharge, massicott, or protoxide of lead, as hereinbefore de. scribed. Ibid. Progress of PraeUcal and Theoretical Mechanics and Chemistry.