CEMENTS, MORTARS, PAINTS, AND GLUES. 91 



sharp sand, 10 parts ; blue or red clay and clean iron-filings, 

 of each, 5 parts. Grind together and calcine or heat. 



9. Powdered clay, 6 pounds ; iron-filings, 1 pound. Make 

 into a paste with linseed oil. 



10. Powdered litharge, 2 parts ; silver sand and slaked 

 lime, of each, 1 part ; boiled oil enough to form a paste. 



These cements are used for stopping leaks and cracks in 

 bofiers, iron pipes, stoves, etc. They should be applied as 

 soon as made. 

 Tar Cement. — 



11. Coal-tar, 1 part; powdered slate (slate flour), 3 or 

 4 parts ; mix by' stirring until thoroughly incorporated. 

 Very useful for mending watering-pots, barrels, leaky sash, 

 etc. It remains somewhat elastic. It does not adhere to 

 greasy surfaces. It will keep for a long time before using. 



Copper Cement. — 



12. Beef blood thickened with sufficient finely powdered 

 quicklime to make it into a paste is used to secure the 

 edges and rivets of copper boilers, kettles, etc. Use im- 

 mediately. 



Fireproof or Stone Cement. — 



^ 13. Fine river sand, 20 parts ; litharge, 2 parts ; quick- 

 lime, 1 part; linseed oil enough to form a thick paste. 

 Used for walls and broken stonework. 



Earthenware Cement. — 



14. Grated cheese, 2 parts ; powdered quicklime, 1 part ; 

 fresh white of egg enough to form a paste. Use as soon as 

 possible. 



For fine earthenware, liquid glue may be used. 

 Cement for Glass. — 



15. Methylated spirit (wood alcohol) to render liquid a 

 half dozen pieces of gum-mastic the size of a large pea ; in 

 another bottle dissolve the same quantity of isinglass, 

 which has been soaked in water and allowed to get surface 

 dry, in 2 ounces of methylated spirit; when the first is 

 dissolved add 2 pieces of gum-galbanum or gum-ammoniac ; 

 apply gentle heat and stir ; add the solution of isinglass,' 



