Miscellanies. 173 



receives the filtered water, which is drawn off through the stopcock 

 M. F, is a cock for emptying the machine when necessary for 

 cleaning. 



The sand and gravel must be carefully washed before using, and 

 the charcoal carefully selected and free from taste. If this box be 

 nine inches square at the bottom, and thirteen inches high, it will be 

 sufficient for an individual. Larger dimensions may adapt it to fam- 

 ily use, and if made higher in proportion to its breadth than the 

 above ratio, the filtration would be more thorough. The materials 

 should be renewed once in five or six months, or oftener, if ne- 

 cessary. 



13. To render Oil casJcs impermeable. (J. G.) — When the cask 

 is new and ready to receive the oil, pour into it a concentrated and 

 hot solution of sulphate of soda, (Glauber's salt,) spread it well over 

 the whole interior surface by a sponge, cloth or broom, so that the 

 wood may become thoroughly impregnated with the liquor. When 

 it begins to grow cold, withdraw it, heat it again to boiling and renew 

 the operation three or four times. Wipe off the superfluous salt 

 with a coarse cloth, let it dry a few hours, replace the head, (the 

 inside surface of which should have been treated in the same man- 

 ner,) and it will be found that the pores have been effectually stopt 

 by the salt, so that the oil may be safely introduced. 



14. To purify cold short iron, a very simple process is practised 

 in some bloomeries, which consists in throwing on the loupe at the 

 moment when it is formed, half a shovel full of powdered flux, and 

 keeping it afterwards exposed to the air of the bellows for a few mo- 

 ments, before it is carried to the hammer. The flux thus employed, 

 is a limestone, which yields lime of good quality. Its effects on 

 the loupe, are very prompt, depriving the iron of the siderite or phos- 

 phate of iron, which as is well known, renders the iron brittle when 

 cold.— (J. G.) 



15. Method of Bronzing Iron andGun barreh. (J.G.) — Gun bar- 

 rels when damasked, are less liable to rust, and any of them, of whatev- 

 er price, may be treated by a very simple method, which will diminish 

 their readiness to oxydize. When the iron is well scraped and clean- 

 ed, cover its surface with a coating of butter of antimony. If one is 

 not sufficient, two or three coatings may be given. The iron thus 

 acquires a horny reddish brown color, which is not unhandsome, and 



