IMPROVED MUFFLES. O*'^ 



tanco bet-.veen the two results, when I deducted the quantity 

 of water in this spirit calculated from its specific gravity. 



(To he concf tided in our next. J 



V. 



Description of an improved Mode of constructing Muffles for 

 Chemical Purposes, by Mr. Edmund Turrell, A"^o. 40, 



liaxvstorue- Street, Gosxodl-Stieet Road'*'. 



.AV^ING experience] much inconvenience in the common Common 

 mode of moulding mufiles on wooden blocks, for the use of [1]° niuffleTiu^ 

 chemists, enamellors, Sec, I beg leave to lay before your coiiTeiuient. 

 praise-worthy Society, an -improved method, possessing the 

 following advantages: namely, 



First, By this new method of moulding muffles, coarser and Advantages of 

 cheaper materials may*be used than can be ernployed in the 

 common mode; and which also gives them the valuable pro- 

 perty of resisting a greater degree of heat. 



Secondl}', That much time will be saved by this injproved 

 method of manufacturing them, must be allowed, when the 

 two modes are compared. 



Thirilly, The certainty of making them without cracks or 

 flaws, and with coarser materials, will appear obvious, when it 

 is considered, that by this improved method, they are inter- 

 nalhj moulded instead of externaUij ; by which means the 

 strength of the operator may have its full effect, in firmly 

 compressing the composition into the mould. 



In the old mode, the workman, after having spread Disadvantages 

 the composition upon a cloth, guessing at its thickness, '^^ 

 bends it over the block in the best way he can; and by thus 

 disturbing the composition, he must needs make many cracks 

 and flaws, which can be but imperfectly closed in smoothing 

 the surface of the mufiHe while upon the block; the evil con- 

 sequence attending which is, its being subject to fly or crack 



• Transactions of the Society of Arts, for 1807, p. 38. Ten guinea* 

 were voted to Mr. Turrell for this invention. 



Vol. XXL— Dec. 1808. T when 



