(3) ;Linseed oil 2 lbs., cottonseed oil 1 lb., petroleum 1 lb., raw turpentine 2 lbs., castor oil 1 lb., sulphur 2 lbs. Mix well and boil for half hour.

(4) ;Linseed oil 2 lb., cottonseed 1 lb., petroleum 2 lb., raw turpentine 1/2 lb., liquid coal tar 2 lb., spirits of turpentine 1 lb., rubber 4 lbs., sulphur 2 lb. Mix well and boil for 1 hour.

(5) ;Cotton-seed oil 14 lb., linseed oil 14 lbs., asphaltum 8 lb., coal tar 8 lbs., sulphur 10 lbs., camphor 1/2lb. Mix the tar and asphaltum first with the cotton-seed oil, then add the linseed oil and camphor, and then when the temperature is about 270° F. add the sulphur.

(0) Cotton-seed oil 27 lbs., coal tar 30 lbs., earthy matter 5 lbs. Mix and heat to 300° F., strain and cool to 200° F. Add 27 lbs. of linseed oil, heat to 220° F. and add 15 to 18 lbs. of sulphur, continue to increase the heat until the whole is sulphurised. At 240° F. add 1 to 11/2 oz. of nitric acid, and at 270° to 280° F. add 1 to 3 oz. of camphor. To 30 lbs. of the above compound add Para rubber 20 lbs., litharge 5 lbs., and sulphur 1 lb.

Rubber Stamps

It sometimes happens that a rubber stamp to mark a number of papers, or articles is wanted in a great hurry, and that rather than wait for one to be made in the usual manner, it is dispensed with altogether, and each article or paper marked by hand. Anyone with a steady hand and a little patience can make a very good stamp in a more or less short time as follows. Obtain a number of pieces of broken hacksaw blade, cut into about 4-in. lengths, reduce the width at one end to say 1/4in., grind or file these ends to a variety of cutting shapes, such as flat chisel, half round, and pointed knife edge. Harden well, and sharpen well on an oilstone, also make several different size small gouge-shaped chisels, sharpen these likewise. Then obtain a piece of ordinary india rubber of a size sufficient to carrv the whole of the marking required. Mark out on this the letters, figures, or design wanted, but marking all backwards. Hold in front of a mirror and correct any mistake or faulty shape. Moisten the chisel etc. edges with water, and cut away to a depth of, say 1/16in. all the rubber not required to make any impression on the paper, if the tool edges are really sharp, and kept wet while cutting, no trouble at all will be found in cutting away the rubber. Be careful not to cut away any part required to make an impression, and do not destroy the original flat surface of the piece of rubber, i.e., the tops of the letters, etc., as this will spoil the neatness of the impression. Mount the whole on a piece of flat-topped wood for a handle, using good glue or Chatter-ton Compound. A very serviceable stamp is thus made, easily and quickly. An ordinary inking pad is, of course, required. To save time the handle can be done without, and the pieces of rubber held direct by the fingers. Of course the above-mentioned special cutters can be done without, and a small sharp penknife used instead, but greater care will be required to make a first class result in that case.