The Amateur's Oxy-hydrogen Blowpipe SO many interesting experiments may be performed with the oxy-hydrogen blowpipe that it is almost an essential of the amateur's laboratory. With it not only may any of the metals (platinum and iridium not excepted) be fused, but earthy bodies as well may be combined with various metallic oxides. The blowpipe illustrated herewith was designed by the writer, and used for many years. The construction is very simple. Procure a swivel joint, such as is illustrated in Fig. 1. If a joint of that exact type cannot readily be found, the amateur may devise one from the fitting! of a gas light bracket. This jOint should be firmly secured to a base of hard wood, such as mahogany. An ordinary brass blowpipe, of the type used in the mouth, should be secured to the swivel joint, as indicated at a in Fig. 1. The best way to do this is to cut off the lower e:ld of the blowpipe with a triangular fle, twist a piece of copper wire around the end, and press it into the joint, and then secure it by soldering it with soft solder. The joint should be air·tight. The other part of the swivel joint should be fitted with a device such as illustrated in Figs. 2 and 3. It consists of a piece of brass or copper pipe, of %-inch outsid- diameter. With a hack-saw make a cut in the pip- at the middle, as indicated at b, c, Fig. 2. Insert a small strip of brass or tin plat- in this cut and solder it firmly in place, making sure that the joint is air-tight all around, so that the pipe is divided into two separate compartments. Drill two small holes in the tube, one at each side of the tin partition. Then solder a nipple d to the brass tube, so that it fits over the holes just referred to. In every case the soldering should be so done as to prevent leakage of gas or air at the joints. The nipple d should be screwed into the swivel joint, as indicated in Fig. 1. The two sections of the pipe may be connected by rubber tubing to the oxygen and hydrogen sources of supply. In order that the rubber tubing may be firmly held to the brass pipe, it is best to solder a rinp of brass wire to the edge, forming a flange. The hydrogen (carbureted) may be obtained from a gas bracket after removing the tip or burner. The other side of the tube, marked 0 in Fig. 3, should be connected to the oxygen supply, which may either be a cylinder of compressed oxygen, a gas holder, or a gas bag. In use, first turn on the hydrogen or the coal gas and light it at the nozzle of the blowpipe. Then gradually turn on the oxygen. The two gases will commingle in the nipple d. and in the swivel joint, and the presence of the oxygen in the gas will immediately be attended by a reduction of the length of the flame. Turn on the oxnn slowly until a very brilliant bluish green flame protrudes from the blowpipe nozzle. This will indicate the hottest flame obtainable from tle mixture. In case of an -xcess of oxygen, the mixture ^ will ignite within the blowpipe, producing an explosion, which, however, will not be of serious proportions. A piece of battery carbon forms a very good fusion plate upon which the material to be treated may be placed. Slate dust, graphite, glass powder, and many of the metallic oxides, may - be f u s - d wit h this blowpipe. A small quantity of powdered ' borax aids the fusion of the oxides. Metals of any kind may be welded together, even platinum. The blowpipe may be used to produce a brilliant lime-,. light by letting the . fame impinge upon a stick of common lime, mounted on the end of an iron wire rod, and shaped with a file with a hole at the center of the cut drilled with a brad awl. A light of from 200 to 400 candle-power can “hus be produced, with which excellent photographs may be taken at night. Experiments can also be made with blocks of mag- nesia, zinc oxide, oxide of zirconium and compounds of these and other infusible oxides, all of which will give a brilliant light of varying color generally without fusing. Dissimilar metals can be joined in the form of wire without special fluxes. Should a flux be required, boraX answers the purpose very well, or boracic acid. The fusing together of different metallic oxides by the aid of boracic acid flux will often produce excellent imitations of precious stones. An excellent illustration of the explosive properties of a mixture of oxy·hydrogen gas can be shown by blowing soap bubbles with the blowpipe, and allowing the bubble to float in the air; then apply a lighted taper. The report upon ignition will be deafening. A soap bubble blown at the tip of the blowpipe, and the gas supply cut off will act in the same way, but it is better if it be allowed to float in the air.