11^ ON EVAPORATING FURNACES. 



and by heating a mixture oi" thefe fubftances he facceeded m 

 forming the fait artificially. The fuccefs of his experiment 

 fcems to prove the truth of the theory, at leaft in the parti- 

 cular inftance in which he obferved the efflorefcence : but in 

 thofe cafes where the fait evidently proceeds from the fub- 

 ftance of the brick, and where the magnefia has been found 

 to exift previoufly in the clay, the idea of Mr. Gregor appears 

 lefs applicable, fo far as regards the origin of the magnefia ; 

 but in both the procefles the fulphuric acid is equally fuppofed 

 to be derived from the pyrites. Mr. Gregor fuggefts that coal 

 afties might have been mixed with the clay of which thefe 

 bricks were formed ; but I find upon enquiry that this was 

 not the cafe. 



I am, 

 Liverpool, Aug. 30, Your obedient fervant, 



1803. JOHN BOSTOCK. 



X. 



Philofophical Obfervations on the Caufes of the JmperfeSiion of 

 evaporating Furnaces, and on a New Method of conJiruSiing 

 them, for the economical Combuftion of every Defcription of 

 Fuel. By C. CuSaudau, correfponding Member of the 

 Pharmaceutic Society of Paris *. 



On the com- iNoTWITHSTANDING the attempts already made t» 

 buftion of fuel introduce oeconomy in the ufe of the combuftibles neceflary to 

 of furnaces. *^^ manufaftures, we ftill ufe them with confiderable wafte. 

 In all cafes a much greater quantity of fuel is confumed than 

 is needful to keep up the ebullition in evaporating furnaces, 

 or to produce the requifite temperature in furnaces for other 

 purpofes. It may be eafily conceived that this fuperfluous con- 

 fumption muft in large eftabliftiraents be attended with great 

 lols, and muft eventually tend to produce a fcarcity of fuel in 

 the market. It therefore becomes us for both reafons to en- 

 deavour to prevent a fcarcity, of which future generations 

 might with juftice accufe us of being the authors, unlefs. we 

 ferioufly occupy ourfelves in fearch of the methods of burning 

 wood with more economy. Many very remarkable improve- 



* Yxom \ht Annates dt Ghimit, No. 138. 



ments 



