102 ANNUAL OF SCIENTIFIC DISCO VEKY. 



ture with an ordinary painter's brush over the surface of the stone, which is 

 then cleaned with pumice-stone or other fine grit, and clean water. 



Ransome's process for preserving stone, which has received high com- 

 mendation in England, consists in coating the stone or other material first 

 with a solution of a soluble silicate, and afterward applying a solution of 

 chloride of calcium, with a view of forming an insoluble silicate of lime in 

 the body of the stone. In place of a soluble silicate and chloride of calcium, 

 other preparations may be used ; the invention consisting in the application 

 in succession of two solutions, which, by mutual decomposition, produce an 

 in insoluble substance, which is deposited in the structure and on to the sur- 

 face of the stone or other material. It is claimed that this application not 

 only prevents new stone from decaying, but effectually prevents the further 

 decay of that which is already rapidly approaching disintegration. The ef- 

 ficacy of this mineral is not confined to stone alone, but may be applied to 

 brick, lime, stucco, etc., with equally effective results. 



NEW WATEK-FROOF GLUE. 



The following is the composition of a new water-proof glue, which is said 

 to be superior to the well-known " Jeffries' Marine Glue." 



Dissolve one-fourth of a pound of common glue in water the usual way ; 

 then dip into it some clean white paper, sufficient to take it all up. When 

 the paper is nearly dry, cut it into strips and put them into a common glue 

 pot ; add one pound of alcohol, and boil gently for one hour. Then take 

 out the paper the only use of which is to give the glue more surface for 

 the action of the alcohol and add one fourth of a pound of powdered gum 

 shell-lac ; continue the heat, gently stir the mixture until the shell-lac is dis- 

 solved, and then evaporate it to the proper consistence for use. For cement 

 add more shell-lac and prepare it thicker. 



Elastic Glue M. Lallemant, of Paris, finds that by mixing gelatine 

 with an equal weight of glycerine, it is rendered permanently clastic, and 

 is preserved from putrefaction. This material may be used for dentist's 

 purposes, for printers' inking rollers, &c. 



XEW GOLD YAEXISH. 



A beautiful and permanent gold varnish, which does not lose its color by 



I exposure to light and air, may be thus prepared : two ounces of best 



1 French garancine to be digested in a glass vessel with six ounces of alcohol 



of specific gravity of 0,833 for twelve hours, pressed and filtered ; a solution 



of clear orange-colored shell-lac in similar alcohol is also prepared, filtered, 



and evaporated, until the lac has the consistence of a clear syrup. It is then 



colored with the tincture of garancine. Objects coated with this have a 



color which only differs from that of gold by a slight brownish tinge. The 



color may be more closely assimilated by a little tincture of saffron. 



Moulds of Stearic Acid and Shell-lac for Galvanoplastic Copies. The best 

 material for moulds is prepared from equal parts of stearic acid and shell- 

 lac. The stearic acid is melted first, and the shell-lac is then added in small 



