Page:Popular Science Monthly Volume 88.djvu/626

 598

��Popular Science Monthly

��Making and Using a Small Still AMATEUR chemists and photog- l\. raphers as well as other experi- menters often find themselves in need of pure or distilled water. This still will prove a help and is an interesting ap- paratus to make. It is easily operated and will distill a comparatively large quantity of liquid.

The principle of distillation is the mere raising of a liquid to its vaporizing point and the collecting and condensing of its vapor. The most important part of the still is the condenser, which is shown in the detailed diagram. It consists of a large glass tube about 13^:4 ins. in diameter and about 12 ins. long. Each end is sealed tightly with a good sound cork stopper.

Three tubes known as the condensing coils are about ^ in. in diameter and 16 ins. long, and are passed through the

���CcnCEtti^£.R

���P^

��a-^^pa^igemEmt of afpaitatus

��Diagram of the arrangement of apparatus for a small still

Stoppers and glass casing. Tv.'o short lengths of tubing are placed in the corks to allow the cooling water to enter the casing and to provide an overflow outlet. The condenser ends should be painted with shellac or dipped into molten paraffin wax to seal any leaks. Connect the three coil tubes with rubber tubing, as shown, to make one continuous circuit, and to allow the vapor to enter one end and pass through the casing thre-:' different times before the condensed liquid emerges. ]\Iount the casing upon a wooden base with two brass straps.

The diagrammatic arrangement of the apparatus shows the system of operating. The boiler is easily made from a can and small funnel as shown. Solder the fun- nel carefully to the top of the can. Fill the boiler by submerging in the liquid. Use a Bunsen burner or alcohol lamp for vaporizing the contents. Connect the boiler to the inlet of condenser by mean. of rubber tubing. A vessel of co'd

��water is used to cool the condenser, the water being siphoned to the water inlet on the condenser through tubing. Make certain that the coil tubes are entirely

���Detailed diagram of the condenser

covered with the cooling water to insure perfect condensation. Allow the waste water to drain off and collect the dis- tillate in a clean vessel.

Remember that distillation is based upon the principle that the boiling points of different liquids differ. With this in mind many interesting experiments can be made with the apparatus described. Any desired liquid may be removed from a mixture of various liquids by keeping the boiling point of the mixture the same as that of the desired substance.

The boiling points of some common liquids at sea level are as follows:

Water 212° Fahr.

Alcohol 173° Fahr.

Ammonia 140° Fahr.

Chloroform 140° Fahr.

Saturated Salt Sol. 226° Fahr.

Turpentine 315° Fahr.

Sulphuric Acid 590° Fahr.

Ether 100° Fahr. — B. F. Dashiell.

Straightening Kinked Wire

KIXKED wire can be straightened satisfactorily with two blocks of v.ood, cut and fitted as shown in the accompanying drawing, and bolted to- gether loosely. The wire is passed between them, wrapped around a short strip of hard wood and pulled with a firm, even pressure.

���Crooked wires can be straightened out by

merely running them between these two

blocks of wood

�� �