4*24 Miscellaneous Intelligence. 



this is the last operation previous to its distribution. — Tech. Rep. 

 i. 51 6. We apprehend this process would not suit the London taste. 



8. Preservation of Steel Goods. — Mr. Aikin recommends a thin 

 coating of caoutchouc as an excellent preservative of iron and steel 

 articles from the action of the air and moisture ; its inalterability, 

 consistence when heated, adhesion to iron and steel, and facility 

 of removal, render it an admirable substance for this purpose. 



The caoutchouc is to be melted in a close vessel, that it may 

 not inflame. It will require nearly the temperature of fusing 

 lead, and must be stirred with a horizontal agitator rising through 

 the vessel, to prevent burning. Plates of iron and steel, partly co- 

 vered with this composition, gave full proof in the laboratory of 

 the protection afforded by the caoutchouc film to the metal. 



Mr. Parkins, to whom Mr. Aikin communicated this process, 

 has made much use of it in his blocks, plates, dies, &c. He mixes 

 some oil of turpentine with the caoutchouc, which renders it easily 

 applicable, and leaves the substance, when dry, as a firm varnish 

 impermeable to moisture. This, when required, is easily removed 

 by a soft brush dipped in warm oil of turpentine. — Tech. Reports, 

 i. 55. 



p. Preservation of Eggs. — Eggs may be preserved, according to 

 M. Cadet, a great length of time in lime-water containing excess 

 of lime. An cAellent mode of preserving them also, is to place 

 them for about 20 seconds in barley-water ; then remove, dry, and 

 put them by. Eggs may be well salted throughout, if laid in brine 

 for 8 or 10 days, and may then be preserved a great length of time. 



10. Fusible Metal, and its application.- — A combination of three 

 parts of lead, with two of tin and five of bismuth, forms an alloy 

 which melts at the temperature of 197° F- I" making casts with 

 this and similar alloys, it is important to use the metal at a tempe- 

 rature as low as possible; as if, but a few degrees elevated, the 

 water which adheres to the things from which casts are to be 

 taken, forms vapour, and produces bubbles. Mr. Varley allows 

 the fused metal to cool in a tea-cup until just ready to set at the 

 edges, and then pours it into the moulds, procuring in this way 

 beautilul casts from moulds of wood, or of other similar sub- 

 stances. When taking impressions from gems, seals, &c., the 

 fused alloy should be placed on paper or pasteboard, and stirred 

 about till it becomes pasty from cooling ; at which moment the 

 gem, die, orseal, should besuddenlystarapedonit, and a verysharp 

 impression will then be obtained. 



Mr. Gill has applied the fusible alloy to the formation of me- 

 tallic pencils. The metal is cast into a proper form in a piece of 

 paper over a candle. A sheet of drawing-paper is prepared by 

 having a little prepared hartshorn, (i. e., finely divided calcined 



