MECHANICAL. 793 



the solution up to this standard— the silver, therefore, that is deposited upon 

 the articles being plated, dissolved off of the " plate, sheet, or piece of pure 

 silver," as it is deposited upon the articles — the solution remaining full strength 

 and ready for continued use. Of course the " battery" is connected with this 

 " plating solution," 



Remarks.— HhQ battery used is the same as used by telegraphers, who will 

 instruct one how to prepare and " connect " it. All articles to be plated must 

 be freed from grease with a solution of potash or soda, as in the above pro-- 

 cesses. This is from a friend in Ann Arbor, whom I know to be reliable from 

 over 25 years acquaintance. 



Steel— To Temper Very Hard.—" Take water, 2 measures— no mat- 

 ter what size — wheat flour, % measure, and 1 of common salt. 



Directions. — Mix into a paste ; heat the steel to be hardened enough to coat 

 with the paste — by immersing it in the composition — after which heat it to a 

 cherry red and plunge it in cold, soft water. If properly done, the steel will 

 come out with a beautiful white surface, and very hard." 



Remarks. — It is said this is the process by which Stubbs' flies are tempered, 

 which are recommended below, for drilling glass. 



1. Stieel and Iron Machinery— To Keep Prom Rusting.— 

 Powdered camphor gum, 14 oz. ; lard, 1 lb. ; a httle black lead. 



Directions. — Dissolve the gum in the lard by heat; remove the scum, stir 

 in just black lead enough to give an iron shade. Rub this over cleaned steel or 

 iron machinery of any kind, and leave on 24 hours; then rub with a soft linen 

 cloth, and it is safe from rust for a long time. 



Iron or Steel Varnish— To Prevent Rust.— Rosm, 120 parts (drs., 

 ozs. or lbs.); gum sandarach, 180; gum lac (shellac), 60; spirits of turpentine, 

 120; and alcohol, 180 parts. 



Directions.— Pulverize the three first articles and melt together; and 

 gradually (and carefully, to avoid taking fire), add the turpentine, continuing 

 the heat until all are again dissolved (if they harden) in the turpentine; 

 then add the alcohol, and filter through a fine cloth (muslin) or thick filtering 

 paper, bottle and cork for use. — Manufacturer and Builder. 



Remarks.— The straining or filtering indicates its intention for fine articles; 

 without it, it would do for outside railings, or ornamentation; and if desired black, 

 for iron balustrades, fence, etc., add a Uttle fine lamp-black, which will adapt 

 it to such work, and look very nicely. See also Black Paint How to Make 

 for Iron Work. 



3. Steel— Rust Upon— To Remove.— Cover the steel for a couple 

 of days with sweet oU; then with finely powdered unslacked lime (known as 

 "quick" lime), rub the steel until all the rust is removed; re-oil to prevent 

 further rust. — Indian Domestic Economy. 



2. Another plan, is, to place the rusty article in a bowl of kerosene 

 else to wrap the steel in a cloth well wet with kerosene, and let it remain 24 

 hours, or more; then scour the rusty spots with brick dust. 



