113' Memorandums, Hints, Precepts, and Recipes, 



other veflel diflblve as much ifinglafs (which has been pre- 

 vioufly foaken in water till it is Iwollen and fofi) in French 

 brandy or in rum, as will make two ounces, bv meafure, ot 

 firong glue, and add two iinail bits of gum-galbannm or am- 

 moniacuni, which mull be rubbed or ground till they are 

 dinblved : then mix the whole with a fufficicnt heat; keep 

 it in a phial ftopt, and when it is to be uied let it in hot 

 water. — Eton's Survey of the Turkijb Empire. 



XVI. The proccfs above deicribed may be limplificd by 

 adding the gum-ammoniac to the ifmglafs during its folutiou 

 in proof fpirit, and expofmg the mixture to a boiling heat 

 imtil it is dilfolved, when the folution of mallic in alcohol 

 may be added. The gum-ammoniac previoufly diflblved 

 with the ifinglafs promotes the union of the niaftic with the 

 mucilage. This cement has been tried in London, and found 

 to anfwer well ; it ftands againll moifture. 



Cements which rejijl Moijlure. 



Generally fpeaking, all cements into the compofition of 

 which gum-lac or maftic enters, of which we have already 

 given fome, poflTefs this property. 



XVII. A cement of this kind may be made by difToKing 

 ifinglafs in proof fpirit, to which muft afterwards be added a 

 folution of fliell-lac in alcohol. 



XVIII. Another cement, which will alfo refift moifiure, 

 may be formed by melting by heat, without water, common 

 glue with half its weight of refin, to which mult be added 

 icnne red ochre to give it body ; it is particularly ufeful for 

 cementing hones to their framfs. 



XIX. Carpenters employ a cement in framing fign-boards. 

 Sec. to ftand the weather, which they make by adding to 

 a pint of well made common glue (made with water) an 

 eighth part of that quantity of boiled linfeed oil, dropping it 

 into the glue gently, and flirring it all the time. 



XX. White lead ground up with boiled linfeed oil to the 

 confiftcnce of paint, makes a good cement for joining broken 

 porcelain, earthen ware, and glafs articles deftined to hold 

 water, 6<-c. After the cement is applied, between the pieces 

 they fliould be prefTod home to each other as dole as poffible. 

 The clofer the better ; nor need any fears be entertained that 

 enough of cement will not be left in the joint ; for the thin- 

 iieft tilm that can be interpofed will hold firmer than a thicker 

 one would. The articles (liould remain undilturbed for two 

 or three months, and before ufing them the cement flicking 

 on the outfide of the joint fliould be carefully fcraped oft' with 

 a knife. 



XXI. A 



