442 



MECHANICAL. 



boiled oil, and let the whole boil for two 

 hours over a slow coal fire. When dis- 

 solved, add again six pounds of boiled 

 linseed oil, and one pound of litharge, 

 and boil until an even liquid is obtained. 

 It is applied warm. 



i. Gutta-Percha Varnish. — Clean a 

 quarter of a pound of gutta-percha in 

 warm water from adhering impurities, dry 

 well, dissolve in one pound of rectified 

 resin oil, and add two pounds of linseed 

 oil varnish, boiling hot. Very suitable to 

 prevent metals from oxidation. 



VARNISH, Hair. — Dissolve one part 

 of clippings of pig's bristles, or of horse- 

 hair, in ten parts of drying linseed oil by 

 heat. Fibrous materials (cotton, flax, 

 silk, etc.), imbued with the varnish and 

 dried, are used as a substitute for hair- 

 cloth. 



VARNISH, for Iron.— Take oil of tur- 

 pentine, add to it drop by drop, and while 

 stirring, strong sulphuric acid,, until a 

 syrupy precipitate is quite formed, and no 

 more of it is produced on further addi- 

 tion of a drop of acid. The liquid is 

 now repeatedly washed with water, every 

 time refreshed after a good stirring, until 

 the water does not exhibit any more acid 

 reaction on being tested with blue litmus 

 paper. The precipitate is next brought 

 upon a cloth filter, and, after all the water 

 has run off, the syrupy mass is fit for use. 

 This thickish magma is painted over the 

 iron with a brush ; if it happens to be too 

 stiff, it is previously diluted with some oil 

 of turpentine. Immediately after the 

 iron has been so painted, the paint is 

 burnt by a gentle heat, and, after cooling, 

 the black surface is rubbed over with a 

 piece of woolen stuff, dipped in and 

 moistened with linseed oil. 



According to the author, this varnish is 

 not a simple covering of the surface, but 

 it is chemically combined with the metal, 

 and does not, therefore, wear off or peel 

 off, as other paints or varnishes do from 

 iron. 



VARNISH, Japan, Black.— Bitumen, 

 2 ounces; lampblack, i ounce; Tur- 

 key umber, one-half ounce; acetate 

 of lead, one-half ounce ; Venice turpen- 

 tine, one-half ounce; boiled oil, twelve 

 ounces. Melt the turpentine and oil to- 

 gether, carefully stirring in the rest of 

 the ingredients, previously powdered. 

 Simmer all together for ten minutes. 



VARNISH, Mahogany. — Sorted gum 

 anime eight pounds, clarified oil three 

 gallons, litharge and powdered dried 

 sugar of lead, of each one-fourth ot 

 pound; boil till it strings well, then cool 

 a little, thin with oil of turpentine five 

 and one half gallons, and strain. 



VARNISH, for Oil Paintings.— Digest 

 at a slow heat gum sandarach, two parts \ 

 gum mastic, four parts; balsam copaiva,. 

 two parts; white turpentine, three parts j 

 with spirits of turpentine, four parts \ 

 alcohol (ninety-five per cent.) fifty-six 

 parts. 



VARNISH, for Paintings and Pictures. 

 — Honey, one pint; the whites of two 

 dozen fresh eggs; one ounce of good 

 clean isinglass; twenty grains of hydrate 

 of potassium; one-half-ounce of chloride 

 ot sodium; mix together over a gentle 

 heat of eighty or ninety degrees Fah. 

 Be careful not to let the mixture remain 

 long enough to coagulate the albumen ot 

 the eggs; stir the mixture thoroughly, 

 then bottle. It is to be applied as fol- 

 lows: one tablespoonful of varnish 

 added to one-half-tablespoonful of good 

 oil of turpentine, then spread on the pic- 

 tures as soon as mixed. 



VARNISH, Oak.— a. Clear pale resin, 

 three and a half pounds; oil of turpen- 

 tine, one gallon; dissolve. 



b. Clear Venice turpentine, four pounds \, 

 oil of turpentine, five pounds; mix. Both 

 are good common varnishes. 



VARNISH, Red Copal.— a. Vermilion, 

 red oxide of lead (minnium), red orchre, 

 or Prussian red, etc., and proceed as 

 before. 



b. Dragon's blood, brick red, or Vene- 

 tian red, etc., and proceed as before. 



VARNISH, for Straw Hats.— Take 

 either red or black sealing wax ; to every 

 two ounces of sealing wax, add one ounce 

 of rectified spirits of wine; pound the 

 wax fine, then sift it through a fine lawn 

 sieve, till you have made it extremely 

 fine; put it into a large phial with the 

 spirits of wine; shake it; let it stand 

 near the fire forty-eight hours, shaking it 

 often ; then with a brush (a hog's bristle 

 brush) lay it all over the hat (or basket). 

 Let it dry and then repeat the operation. 



VARNISH, for Stoves.— Melt half a 

 pound of asphaltum, and add to it a 

 quarter of a pint of linseed oil, and one 

 pint of turpentine. This quantity will be 



