E represents a pair of tweezers, which should be made of good spring wire flattened at the ends. F is a clamp for mounting microscope slides, and for holding small objects to be cemented or soldered. G is a pinch cock for rubber tubing; its normal position is closed, as in the engraving, but the end a is capable of engaging the loop b, so as to hold the pinch cock open. H shows a clamp or pinch cock having a wire c hooked into an eye in one side, and extending through an eye formed in the other side. This wire is bent at right angles at its outer end to engage a spiral d, placed on it and acting as a screw. The open spiral is readily foemed by wrapping two wires parallel to each other on the same mandrel, and then unscrewing one from the other. The handle will of course be formed by aid of pliers. I shows still another form of pinch cock. It is provided with two thumb pieces, which are pressed when it is desired to open the jaws. K is a tripod stand, formed by twisting 3 wires together. This stand is used for supporting various articles, 6uch as a sand bath or evaporating dish, over a gas flame.
It is also useful in supporting charcoal in blowpipe work.
L shows a stand adjustable as to height for supporting the beak of a retort, or for holding glass conducting or condensing tubes in an inclined position. The retort or filter stand, represented in M, is shown clearly enough to require no explanation. Should the friction of the spiral on the standard ever become so slight as to permit the rings to slip down, the spirals may be bent laterally, so as to spring tightly against the standard. N shows an adjustable test tube holder, adapted to the standard shown in M, and capable of being turned on a peculiar joint, so as to place the tube in any desired angle. The holder consists of a pair of spring tongs, having eyes for receiving the notched cork, as shown in 0. One arm of the tongs is corrugated to retain the clamping ring in any position along the length of the tongs. The construction of the joint by which the tongs are supported from the slide on the standard is clearly shown in Oa. It consists of two spirals y h, the spiral h being made larger than the spiral g, and screwed over it, as shown in 0. This holder is very light, strong, and convenient.
P represents a holder for a magnifier, which has a joint, f1, similar to the one just described. The slide k is formed of a spiral bent at right angles and offset to admit of the two straight wires passing each other. This holder may be used to advantage by engravers and draughtsmen. Q shows a holder for a microscope condenser, the difference between this and P being that the ring is made doable to receive an unmounted lens.
Wire apparatus for laboratory use. Laboratory apparatus.
R shows a Bunsen burner, formed of a common burner, having a surrounding tube made of wire wound in a spiral, and drawn apart near the top of the burner to admit the air, which mingles with the gas before it is consumed at the upper end of the spiral.
S represents a connector for electrical wires, which eiplains itself. The part with a double loop may be attached to a fixed object by means of a screw. Another electrical connector is shown in T, one part of which consists of a spiral having an eye formed at each end for receiving the screws which fasten it to its support, the other part is simply a straight wire having an eye at one end. The connection is made by inserting the straight end in the spiral. To increase the friction of the two parts, either of them may be curved more or less.
A microscope stand is shown in U. The magnifier is supported in the ring o. The ring p supports the slide, and the double ring q receives a piece of looking glass or polished metal, which serves as a reflector.
V shows a set of aluminium grain weights in common use. The straight wire is a 1 gf. weight, the one with a single bend is a 2 gr. weight, the one having two bends and forming a triangle is a 3 gr. weight, and so on. W and X are articles now literally turned out by the million. It is a great convenience to have one of these inexpensive little corkscrews in every cork that is drawn occasionally, thus saving the trouble of frequently inserting and removing the corkscrew. The cork puller shown in Y is old and well known, but none the less useful for removing corks that have been pushed into the' bottle, and for holding a cloth or sponge for cleaning tubes, flasks, etc.
Z shows a stand for test tubes. The wire is formed into series of loops, and twisted together at r to form legs. A very useful support for flexible tubes is shown in J. It consists of a wire formed into a loop, and having its ends bent in opposite directions to form spirals. A rubber tube supported by this device cannot bend so short as to injure it. Most of the articles described above may be made to the best advantage from tinned wire, as it possesses sufficient stiffness to spring well, and at the same time is not so stiff as to prevent it from being bent into almost any desired form. Besides this the tin coating protects the wire from corrosion and gives it a good appearance. (Geo. M. Hopkins.)
By this simple device (Fig. 11) the washing of precipitates and the cleansing of vessels used in the process of analysis, which before required the use of the ordinary wash-bottle, can now be done with much more facility and in a shorter time. It consists essentially of a thin glass flask C, placed about 3 ft. above the level of the working desk, and closed by a 3 hole rubber stopper. Through one of the holes issues a rubber tube D (or glass with rubber connections), descending to the desk and ending in a -glass nozzle.
Connection is made by a second hole in the stopper with a reservoir bottle A; placed above the top of the wash-bottle. In the third hole is placed a glass tube bent at an angle to keep out dust. On filling the flask from the reservoir - the flow being stopped by a pinch cock - the water is started by suction from below, and the stream through the nozzle can be regulated or stopped at will by a pinch cock placed conveniently to the hand, the height of the water flask furnishing the pressure, which is sustained by the siphon.
A Bunsen burner H is placed underneath the flask, and the water can be heated when it is so desired. Hot water as well as cold can thus be used in treating precipitates. Other solutions can be employed equally as well as water. (See bottle F.)
The advantages of this system are:
1. The saving of mueh time and consequent labour attending the use of an ordinary wash-bottle, especially where several analyses are carried on at the same time, the exertions required by the mouth and lungs being thereby avoided.
2. No air exists in the tube, as in an ordinary wash-bottle, and consequently the full force of the liquid is utilised immediately.
3. When used with a wash solution of ammonia water, no trouble is experienced with free ammonia, which ordinarily is quite hurtful to the mouth and eyes.
The large bottle £ with the accompanying tube shows a convenient arrangement for holding any solution and delivering the same. (H. B. Battle.)
Figs. 12,14, show Fenner's combined apparatus which can be used as a Water-bath, a percolator, a still, and evaporator, for making tinctures, fluid extracts, solid extracts, infusions, syrups, etc, and for distilling, evaporat ing, etc.
Combined water-bath, percolator, and still.