K. DOMESTIC AND HOUSEHOLD ECONOMY. 451 



dry, and then mixed with as much molasses or sirup as may 

 be necessary to form a plastic mass, about as much as the 

 weight of the dry powder. This dough is well worked, and 

 then formed into cylinders or disks, allowed to dry for some 

 time at a moderate temperature, and then burned in a care- 

 fully heated muffle, without access of air. After being slow- 

 ly cooled, the soluble salts are extracted, and the sulphide of 

 iron decomposed, by placing the article in very dilute hydro- 

 chloric acid. The filter is then thoroughly washed in run- 

 ning water, dried, and again heated to dull redness in a well- 

 closed muffle, and finally shaped, by turning, as may be de- 

 sired, for beakers, funnels, etc. Closed hollow vessels can be 

 formed by luting together two suitably shaped vessels of the 

 substance by means of a certain paste. This is prepared by 

 covering the turnings from the washed masses, thinly, with 

 pure sirup (made by dissolving refined sugar in half its weight 

 of water), and triturating them. The edges of the vessels to 

 be luted are first well fitted together, and then coated with 

 the paste, so as also to fill all the seams ; and the whole, after 

 drying thoroughly, is to be burned at a dull-red heat. While 

 the fused sugar-carbon affords a vitreous mass, the asbestos 

 and coke and coal give firmness and form the framework. 

 The charcoal removes especially fusel-oil and odorous gases, 

 and the nitrogenous animal carbon extractive and coloring 

 matter. Tubes of different materials can be firmly cemented 

 to the filters by plastic sulphur or good cement, such as is made 

 with chalk, clay, and water-glass. 14 C, 1873, CCLX., 39G. 



GLYCERINE FOR PRESERVING LEATHER FROM AMMONIACAL 



VAPORS. 



The addition of a small quantity of glycerine to the grease 

 used for leather articles, exposed to the amrnoniacal exhala- 

 tions of horse stables, is said to have the desirable eft'ect of 

 keeping them soft and pliable. 



INFUSORIxVL EARTH AS A NON-CONDUCTOR OF HEAT. 



Tripolite or infusorial earth, being a worse conductor of 

 heat than coal-ashes, and almost as poor as flax-chaff, and be- 

 ing refractory, is adapted for walls of ice-cellars and fire- 

 proof safes, for casing steam boilers and pipes, etc., and pos- 

 sesses the advantage of affording protection against rats and 



