198 Miscellaneous Intelliyenee, 



that the fused tallow is improved in quality and increased in quan- 

 tity, the fusion very much quickened, and the use of a press dis- 

 pensed with. By the use of close vessels, the fumes evolved can be 

 either conducted to a fire-place to be burnt ; or, if that may be thoupjht 

 dangerous, in consequence of the occasional boiling over of the 

 melting tallow, can be conducted into a condensing apparatus^ 

 which is found readily to condense them. 



M. D'Arcet uses 100 parts of crude tallow in small pieces, 50 

 parts of water, and 1 part of sulphuric acid, sp. gr. 1.848. In some 

 small experiments a digester was used, having a pierced copper 

 plate near the bottom to avoid the necessity of stirring ; 1500 

 (31b. 5oz.) parts of crude tallow, 750 of water, and 124 of oil of 

 vitriol were used, and the fumes conveyed by a pipe into afire-place ; 

 half an hour's ebullition completed the fusion. The infusible 

 matter when pressed in a cloth, weighed only 96 parts, and was 

 slightly acid. The tallow was white, hard, and sonorous, and not 

 acid. Without the acid, the same effect was not produced in an 

 hour. 



A tallow manufacturer then tried the experiment with 2 cwt. of 

 tallow, using the acid, but operating in open vessels ; 92 per cent, 

 of fused tallow was obtained, and 8 of loss occurred : in the ordinary 

 way, 15 per cent, of loss occurred. In a second large experiment 

 with acid, only 5 of loss occurred. The residue does not require the 

 use of a press, but cannot be made into cakes for cattle, unless pre- 

 viously freed from acid by washing. 



Experiments made on the condensation of the vapour was found 

 to succeed very well, and thus all fear of injury from fire is avoided. 

 The Council propose conducting the vapours into the drains of the 

 works and so condensing them there ; no annoyance being appre- 

 hended from the occasional return of the vapours into the building, 

 as that effect can be counteracted by the use of stink traps. — 

 Ann. de V Industrie, i. 295. 



8. Method of hardening Plaster Casts and Alabaster. — The fol- 

 lowing process is described by M. Tissot who has patented it in 

 France. The piece of plaster or alabaster after being shaped, is 

 put for 24 hours into a furnace. If the piece is only 1 8 lines 

 thick, 3 hours in the furnace, heated up to the temperature required 

 for baking bread, is sufficient ; if thicker, it is left in for a propor- 

 tionably longer time. At the end of the time, it is withdrawn 

 with caution and cooled, after which it is put for 30 seconds into 

 river water, withdrawn for a few seconds, and then again immersed 

 for a minute or two, according to its thickness. The piece is then 

 exposed to the air, and at the end of three or four days, has 

 acquired the hardness and density of marble. It may then be 

 polished. — Bull, Univ. E. x. 26. 



9. Injurious Co/owrs.— The Government of Lombardy has issued 



