Henley's Twentieth Century Formulas, Recipes and Processes. Various

together equal parts of gutta percha and ordinary pitch. The pieces to be united have to be warmed.

      Cement For Belts.

      —Mix 50 parts, by weight, of fish glue with equal parts of whey and acetic acid. Then add 50 parts, by weight, of garlic in paste form and boil the whole on the water bath. At the same time make a solution of 100 parts, by weight, of gelatin in the same quantity of whey, and mix both liquids. To the whole add, finally, 50 parts, by weight, of 90-per-cent alcohol and, after filtration, a cement is obtained which can be readily applied with a brush and possesses extraordinary binding qualities.

      Cement For Chemical Apparatus.

      —Melt together 20 parts of gutta percha, 10 parts of yellow wax, and 30 parts of shellac.

      Size Over Portland Cement.

      —The best size to use on Portland cement molding for wall paper would ordinarily be glue and alum size put on thin and warm, made in proportion of 1/2 pound of glue and same weight of alum dissolved in separate pails, then poured together.

      Aquarium Cements.—

I.—	Litharge	3 ounces
Fine white sand	3 ounces
Plaster of Paris	3 ounces
Rosin, in fine powder	1 ounce
Linseed oil, enough.
Drier, enough.

      Mix the first three ingredients, add sufficient linseed oil to make a homogeneous paste, and then add a small quantity of drier. This should stand a few hours before it is used. It is said that glass joined to iron with this cement will break before it will come loose.

II.—	Litharge	1 ounce
Fine white sand	1 ounce
Plaster of Paris	1 ounce
Manganese borate	20 grains
Rosin, in fine powder	3 1/2 pounds
Linseed varnish oil, enough.

      III.—Take equal parts of flowers of sulphur, ammonium chloride, and iron filings, and mix thoroughly with boiled linseed oil. Finally, add enough white lead to form a thin paste.

IV.—	Powdered graphite	6 parts
Slaked lime	3 parts
Barium sulphate	8 parts
Linseed varnish oil	7 parts

      V.—Simply mix equal parts of white and red lead with a little kettle-boiled linseed oil.

      Substitute For Cement On Grinder Disks.

      —A good substitute in place of glue or various kinds of cement for fastening emery cloth to the disks of grinders of the Gardner type is to heat or warm the disk and apply a thin coating of beeswax; then put the emery cloth in place and allow to set and cool under pressure.

      Knockenplombe.

      —If 1 part of thymol be mixed with 2 parts of iodoform we obtain a substance that retains its fluidity down to 72° C. (161.6° F.). If the temperature be carried down to 60° C. (140° F.) it suddenly becomes solid and hard. If, in its liquid condition, this substance be mixed intimately with an equal quantity of calcined bone, it forms a cement that can be molded or kneaded into any shape, that, at the temperature of the body (98° F.), becomes as hard as stone, a fact that suggests many useful purposes to which the mixture may be put.

      Cement For General Use.

      —Take gum arabic, 100 parts, by weight; starch, 75 {32} parts by weight; white sugar, 21 parts, by weight; camphor, 4 parts, by weight. Dissolve the gum arabic in a little water. On the other hand, dissolve the starch also in some water. When this is done add the sugar and the camphor and put in a water bath. Boil until a paste is formed, which must be rather thin, because it will thicken on cooling.

      Strong Cement.

      —Pour over well-washed and cleaned casein 12 1/2 parts of boiled linseed oil and the same amount of castor oil, put on the fire and bring to a boil; stir actively and add a small amount of a saturated aqueous solution of alum; remove from the fire and set aside. After standing a while a milky-looking fluid will separate at the bottom and rise to the top. This should be poured off and to the residue add 120 parts of rock-candy syrup and 6 parts of dextrine.

      Syndeticon.

      —I.—Slake 100 parts of burnt lime with 50 parts of water, pour off the supernatant water; next, dissolve 60 parts of lump sugar in 160 parts of water, add to the solution 15 parts of the slaked lime, heat to 70° or 80° C. (158° to 176° F.), and set aside, shaking frequently. Finally dissolve 50 to 60 parts of genuine Cologne glue in 250 parts of the clear solution.

      II.—A solution of 10 parts gum arabic and 30 parts of sugar in 100 parts of soda water glass.

      III.—A hot solution of 50 parts of Cologne glue in 60 parts of a 20-per-cent aqueous calcium-chloride solution.

      IV.—A solution of 50 parts of Cologne glue in 60 parts of acetic acid.

      V.—Soak isinglass (fish bladder) in acetic acid of 70 per cent until it swells up, then rub it up, adding a little water during the process.

      “Shio Liao.”

      —Under this name the Chinese manufacture an excellent cement which takes the place of glue, and with which gypsum, marble, porcelain, stone, and stoneware can be cemented. It consists of the following parts (by weight): Slaked powdered lime, 54 parts; powdered alum, 6 parts; and fresh, well-strained blood, 40 parts. These materials are stirred thoroughly until an intimately bound mass of the consistency of a more or less stiff salve is obtained. In paste form this mass is used as cement; in a liquid state it is employed for painting all sorts of articles which are to be rendered waterproof and durable. Cardboard covers, which are coated with it two or three times, become as hard as wood. The Chinese paint their houses with “shio liao” and glaze their barrels with it, in which they transport oil and other greasy substances.

      Lutes.

      Lutes always consist of a menstruum and dissolved or suspended solids, and they must not be attacked by the gases and liquids coming in contact with them. In some cases the constituents of the lute react to form a more strongly adhering mass.

       The conditions of application are, in brief:(a) Heating the composition to make it plastic until firmly fixed in place.(b) Heating the surfaces.(c) Applying the lute with water or a volatile solvent, which is allowed to volatilize.(d) Moistening the surfaces with water, oil, etc. (the menstruum of the lute itself).(e) Applying the lute in workable condition and the setting taking place by chemical reactions.(f) Setting by hydration.(g) Setting by oxidation.

      These principles will be found to cover nearly all cases.

      Joints should not be ill-fitting, depending upon the lute to do what the pipes or other parts of the apparatus should do. In most cases one part of the fitting should overlap the other, so as to make a small amount of the lute effective and to keep the parts of the apparatus rigid, as a luted joint is not supposed to be a particularly strong one, but rather one quickly applied, effective while in place and easily removed.

      Very moderate amounts of the lute should be used, as large amounts are likely to develop cracks, be rubbed off, etc.

       A classification may be given as follows:(1) Plaster of Paris.(2) Hydraulic cement.(3) Clay.(4) Lime.(5) Asphalt and pitch.(6) Rosin.(7) Rubber.(8) Linseed oil.(9) Casein and albumen.(10) Silicates of soda and oxychloride cements.(11) Flour and starch.(12) Miscellaneous, including core compounds.

      I. Plaster of Paris is,