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Cleaning Sooty Bricks
coal, puddled bar, or blister steel, and Soft coal smoke has spoiled the appearance
charcoal. The crucibles are made of of my pressed-brick house. How can I remove
clay or graphite, with a capacity of 50 to the sooty deposit ?-G. T. S.
85 pounds. The charge is put into the Make a mixture as follows: One pint crucible, and after melting is allowed to of liquid ammonia; 1 gallon soft soap; 2
the " pounds powdered pumice. A soft, pasty riod,” and then poured into moulds. sub'tance should be the result. Brush the
In American practice, graphite crucidust off the brickwork. Then apply the
bles are used, which are made from a mixture with an ordinary new white- mixture of fire-clay and sand, and about wash brush. At the end of some 20
50 per cent graphite. This mixture is minutes, take a scrubbing brush and use ground, allowed to stand for a few days, it vigorously. Rinse down with a hose, and is then moulded by being pressed into or clean with a large sponge and luke
a wooden mould. When dry, it is baked warm water. The bricks will come out
in a kiln. These crucibles can be used as if new.
about five times, if the successive charges are gradually diminished in amount.
The crucible is charged cold. The
pieces of iron are surrounded with charTesting Incandescent Lamps
coal, with a little manganese, and some
times a little salt or ferrocyanide of potCan you suggest a method of testing incan- assium mixed with it. The crucible, after descent lamps, to find out whether or not they being covered, is placed standing on the will burn?-H. O. J.
coal in a hot furnace. After three hours, during which the contents are melted, the cover is lifted, and the melter examines the charge to determine the length of the "killing" period. During this period, , which is about 45 minutes, the metal is becoming tranquil and is taking silicon from the sand in the walls of the crucible. This silicon prevents blow-holes. At the right time and temperature, the
crucible is lifted out and the slag 'z
skimmed off. The metal is now ready for casting or “teeming.”
The ingots are graded and hammered into bars for different uses. Crucible steel furnishes the finest grades for cut
lery and machine tools; it is superior to A contrivance of the sort here illus
Bessemer and open-hearth steel, because trated will probably meet with your re
pure materials are used and the process quirements. It is made by taking a piece tecting the metal from sulphur gases
is carried on in a closed vessel, thus proof board of such length as may be de
from the fuel. sired, and fitting it with a number of lamp receptacles (Y). These are screwed to the board, and wired.' Such connections as convenience dictates are made.
Pictures by Flash-Light The bulb to be tested is inserted in the Would you please explain how to take a receptacle. A plan view of the device is picture by flash-light?-0. S. shown at Z.
Place a card for a reflector behind the
flashlight, the latter being about 25 Making Crucible Steel
inches from the camera and level with it. Describe the crucible process of making When ready, open the camera shutter, steel?-E. W. R.
as in a time exposure, light the flash, and The materials are bar iron, with char- close the shutter at once.
Concrete Foundations 1. Can you give me some practical points on using concrete for foundations? 2. What is cinder concrete?-J. M. M.
1. The first thing in the use of concrete to be considered is, of course, the mixing of the materials. One part cement, three parts sand, and four parts
reinforcing is advisable, and especially upon soil liable to settle or crack. Old steel rails may be used, where reinforcing is necessary. There is a tendency to use more metal for this purpose than is really needed, however.
Concrete should not be allowed to freeze during setting. Freezing after setting, however, seems to do it no special injury. In foundations, retaining walls, etc., a saturated salt solution is sometimes mixed with the concrete. This prevents freezing, and the material seems to suffer no injury from its presence.
2. Cinder concrete is made by taking boiler cinders and mixing them with cement. The concrete so made weighs far less than stone or gravel concrete. The material loses considerably in strength, however. It does well enough for floors, but should never be used in damp places, as the porous cinders readily absorb moisture. It is equally faulty in the construction of beams and pillars.
AIR-CHAMBER FOR PUMP.
Place of Air-Chamber on Steam Pumps
Where should the air-chamber on a steam pump be placed?—E. B. M.
The air-chamber on the discharge should be placed at the highest point of
the valve-chest and above the delivery broken stone make generally the best
opening so that the air will not tend to
slip out with the water. Even then the proportions. In cases where gravel is easy to procure, this may be substituted
air will be gradually absorbed by the for stone. In the center of a large block
water; and provision must be made for the proportion of stone and sand may be
renewing the air-cushion - either when increased with very satisfactory results.
the pump is not in use, by admitting air Mixed concrete should never be shov
through a cock and allowing some water eled into a hole full of water, as the stone
to escape from the valve-chest; or conor gravel will sink first and the other
tinuously, by an automatic pump. material follow according to its specific
The suction air-chamber should be so gravity. Where it is necessary to lay placed that the stream of water flowing the foundations under water, the dry
to the pump will cushion against the air mixture must be placed in bags and so
in it without changing its direction abdeposited. While the concrete thus as
ruptly. Two positions which fulfil this
condition are shown in the accompanysumes an irregular form, this method has proved highly successful in building ing figure. If it is impossible to place footings. The following method is em
the suction chamber in such a position, ployed where the forms extend clear to
the capacity should be increased considthe bottom under water. A special shovel
erably, the amount depending on the or bucket is filled with the concrete and
speed at which the pump is to be run. lowered to the bottom, where it is emptied.
New Cure for Appendicitis Concrete in foundations, even in large In Germany collangol, a silver solubuildings, is rarely reinforced. Where tion, is curing appendicitis without the the foundation is upon uneven ground, necessity of an operation.
THE Sierra Nevada Mountains climb up the mountain side has cut the
must go to work. Mr. E. H. heart out of profits and diverted conHarriman, the "little wizard" of siderable freight to other lines.
the railroad world, has decided But—as is often the case when great that they have been idle long enough. financial genius and splendid engineering Worse than that, they have been ability take hold of a case together—what an absolute obstruction to transportation. seems almost a miracle has now been acIt has taken three or four panting loco- complished. The mountains themselves motives to painfully pull a short train of are to haul the freight trains to their own loaded freight-cars up the steep grade summits. Harriman has found out how from Truckee, Cal., on the Southern Pa- to lift himself by his boot-straps. cific, to the summit of Emigrant Pass, The little mountain streams, starting about 5,000 feet above sea level. That from the melting glaciers which cap the Copyright, 1907, by The Technical World Company