Scientific.

Waikato Times, Volume XXVII, Issue 2215, 18 September 1886, Page 2 (Supplement)

Scientific .

Waterproofing Papkr. — A new composition for waterproofing paper consists of the following ingredients combined in the proportions stated, viz., resin, 50 per cent. ; paraffin, 45 per cent. ; silicate of soda, 5 per cent. These ingredients are thoroughly mingled by beating them together, and by agitation. The paper to which the composition is applied is usually building or sheathing paper. The latter is taken in the condition in which it conies from the paper machine, being quite dry. A strip or strips of the paper from the roll or other convenient holder are conducted and drawn through the tank of hot composition, whereby the paper becomes well saturated with it, and upon emerging from the tank the paper passes between suitable rolls, which press any surplus composition from it, leaving it hard aud smooth.

Liquid Fuel.— Messrs John Cran and Co,, engineers and boiler makers, are at present experimenting with liquid fuel in boiler heating. An upright boiler of the firm's own special make has been fitted up for the consumption of oil as fuel. The apparatus consists of a nozzle, from which, by the regulation of two valves, oil w forced into the fire-box by steam in the form of a spray. The oil is stored in a tank close at hand, and conducted by a pipe to the floor of the fire-box, where in the special form of "burner" employed it is heated to boiling point by the steam by which it is dispersed. Its flow can, of course, be regulated to suit any required pressure. The boiler supplies steam to the entire engine department of the works. Messrs Cran and Co., who use a cheap residual oil state that the new fuel is as economically as coal at 6s per ton, and claim that its oleanliness and convenience, as well as tha saving of labour involved, are additional advantages which put the old system out of comparison.

Coal Consumption by Locomotives. — In an article on coal consumption as affected by temperature and length of trains, the Railroad Gazette arrives at ' some interesting conclusions. Dead weight to the amount of thirty tons added I to a train of, say, five cars, will not increase coal consumption as much as to adtd another car, both because it does not increase resistance and because the added load decreases somewhat the rolling resistance per ton. If we assume it to add 51b per mile to the coal consumption, we are cortainly not underestimating it proportionally. Adding six tons per car, therefore, to the average weight of a train of five passenger cars means no more than an increase from 551b. to Golb. per train-mile. If we assume this 51b of coal to be worth 1 cent, (at the rate of 4dols. per ton of 20001b for coal), and if an extra passenger at 2 cents, per mile be attracted to the train every third trip, he will pay for the loss of fuel due to adding six tons to the weight of every passenger car of twenty tons or more moved at ordinary train speed, and for each sleeping car of thirty tons or more moved in fast trains making few stops, and the locomotive alone is to be charged with rather more coal than that due to three cars.

How Incandescence is Produced.— The glow of incandescent electric light has become a familiar object to everyone. The little glass bulbs, with their brilliant horse-ahoe of glowing filament, attract no more attention now than the flickering gas jet. But the facts about the gas jet are pretty well understood by nearly everybody, while the electric lamp is atill a puzzle to many people. Both produce light by incandesence. The molecules of ga3 are rendered incandescent by the heat generated by the combustion of other molecules. The blue portion of every gas flame is where combustion is taking place, and from there comes the heat which keeps the rest in a state of incandescence. With the electric light it is the heat produced by the friction of an electric current compelled to go through a fine carbon filament, which raises that filament to a condition of incandescence, and produces light.

New Progress for Manufacturing Car Whef,ls. — The Scientific American states that a*; the works of the Dickson Manufacturing 1 Company, Wilkesbarre, Pennsylvania, a new machine and process, patented by Mr J. J. Carr, have been tested with satisfactory results. It is claimed that, while by the old method of moulding, casting, dressing, and boring the wheels the average product of three men per day was eighteen wheels, with the new procoss the same number of men are able to turn out one perfect wheel every minute, or 720 wheels per day. The principal feature seems to be the substitution of a steel core for one of sand in casting the wheel. Thi* *ias been tried before, but no one ban hitherto hit upon a means of getting this core out of the wheel after it is cast. This is now accomplished by a centre key, which falls out upon a single stroke of the hammer, and lets the steel core drop out, leaving the hole in. the wheel perfectly true, and ready to be put upon the ade without any dressing 1 or boringr. The oand is run into the moulding boxes by a hopper, and both matrices are n* uldod into the pattern drawn out by the single revolution of a shaft driven by steam power. The matrices are carried away upon movable platforms to the cupola, and then the piece ia cast as under the old prooess. The moulding is done as rapidly as a revolving disk can carry the boxes under the passers.