212 ANNUAL OF SCIENTIFIC DISCOVERT. 



to the manufacturers ; or, for the same price, may have many 

 times more brilliant, perfect, and wholesome light than is oflfered 

 them at present. 



In the Drummond light the piece of lime usually emploj-ed 

 crumbles in a few hours. These pencils of compressed magnesia 

 last a week, and, by recent improvements in Paris, crayons have 

 been patented, which have thus far proved to be indestructible, as 

 '* they have been employed for 30 consecutive days without any 

 alteration, being like new." This style of lamp requu-es a dupli- 

 cate tube, — one for the oxygen, and the other for the common 

 illuminating or pure hydrogen gas. 



For furnaces and factories, where the oxygen would be pre- 

 pared on the spot, I learn that it can be generated at a cost of 

 from 2 to 3 dollars a thousand cubic feet ! Any chemist can foresee 

 what a revolution this is destined to produce in metallurgic and 

 other operations where this agent is demanded. Its relation to 

 iron and steel involves millions of dollars. So speedily has this 

 been appreciated abroad that the large steel works in Bradfor I, 

 England, have already made arrangements for the immediate 

 adoption of this process. I learn also that the proprietors of one 

 of the largest iron works in France are negotiating for its use, 

 and that furnaces are being erected for generating oxvo^en by this 

 sj'stem, to be employed in one of the French glass factories at 

 Lyons; in lieu of long chimneys and blasts of diluted oxygen, 

 that pure oxygen is to be used for blowing fires. 



For the economical production of hydrogen gas, to be used as a 

 substitute for coal gas, these chemists employ the hydrates of pot- 

 ash, soda, strontia, baryta, lime, etc., intimatel}' mixed witli cliar- 

 coai, coke, anthracite, or peat, and raise them to a red heat in 

 retorts. 



The reaction between hydrate of lime and fine anthracite coal 

 would be, that the water of tlie hydrate would be deoxidized by 

 the carbon, forming carbonic acid, and hydrogen gas would be 

 liberated : 2 (Ca O, HO) -f C = Ca O -|- CO2 + Ho. 



On remoistening the lime, it again becomes a hydrate, and the 

 process may be repeated. By absorbing the carbonic acid, hydro- 

 gen may thus be isolated with the same facility and at a much 

 lower price than coal gas, with the advantage alluded to of avoid- 

 ing the generation of the ill-odored gases, at the same time utiliz- 

 ing the coal-dust refuse. 



The loss in delivering said gas through lengthened tubes, owinof 

 to its diffusive power, may be overcome by simply coating the in- 

 terior of said pipes with some cheap and impervious lining, at the 

 same time carefully securing the joints. 



CARBOLIC ACID. 



The following are extracts from a lecture of Dr. C. Calvert : — 

 "The disinfectant, or rather antiseptic, properties of carbolic 

 acid are very remarkable. The beautiful researches and discov- 

 eries of M. Pasteur have shown thui all fermtmtation and putre- 



