means of the tubule r', or it may be added through the kettle tubule and evaporated and condensed. We have then an extraction apparatns which will act automatically. The extractive will be deposited in the kettle and may be drained off when desired in the solution of the menstruum used, or it may be obtained in pure form. Should this be desired the lower valve y and the upper valve c' are closed; the valve A' opened, x closed, and E' opened. Thus the evaporated liquid will pass out of the kettle into the condenser, from which it may be collected in whatever place may prove most convenient. This provides the operator with a means of reclaiming the solvents from the percolates. To reclaim the menstruum remaining in the percolated drug, compressed air or steam is forced through the valve Q', and through drug in percolator, and by means of pipe B' into condenser, escaping in condensed form through valve E'.-Amer. Drugg., Dec. 9, 1907, 357-358.

FIG. 7.

FIG. 8.

Soxhlet Extractor-Modification.-Professor Horatio C. Wood, Jr., has devised the modified Soxhlet extractor shown by Fig. 7, which combines efficiency with economy, less fragility, and easy cleaning, while adapted to processes on any desired scale, depending on the selection of the percolator. It consists of a narrow percolator (P), the lower end of which is connected by means of a tightly-fitting cork with a siphon-shaped glass tube (S), and the upper end closed with a cork into which a glass "T"-tube is fitted. The upper end of the tube (T) is connected with a reflux condenser, the side tube with the tube (A), which reaches downward into the biperforated cork, closing the boiling flask (F). The application of the apparatus is obvious. Amer. Journ. Pharm., Mar. 1908, 106.

-F

Soxhlet Extractor.

Extraction

Extraction Apparatus - Convenient Comstruction for Small Quantities.-Jack Apparatus. son and Zanett recommend the simple

apparatus shown by Fig. 8 for the extraction of small quantities of material. It consists of a small flask, surmounted by a reflux condenser, and a glass tube, open at both ends, reaching from the bottom of the flask well into its neck. The powder to be extracted is placed upon a disc of filter paper, resting upon a perforated disc (of porcelain) or other suitable support, which must be above the surface-level of the extracting fluid in the flask, the powder being covered by another disc of filter paper. The condenser must, of course, be adjusted so that the condensed solvent will drop into the extraction-tube.-Pharm. Ztg., lii (1907), No. 99, 1061; from Amer. Chem. Journ., 1907, No. 38, 461.

FIG. 9.

Separatory Funnel-Improved Tap.-P. Soltstein finds that if the axis of the spiggot in the separatory funnel is elongated as indicated in the accompanying illustration (Fig. 9), it can be turned with greater facility and the outflow from the top regulated with greater precision than is possible with the apparatus of the usual construction. He has used this form of separatory funnel for a long time, and has found them extremely convenient. Observing the proportions shown in the cut, these funnels may be constructed of any required capacity.-Pharm. Ztg. lii (1907), No. 93, 971.

Double Separatory - A Useful Device.-Kurt Beysen observes that the process of shaking out with light immiscible liquids, if carried out with the ordinary separatory, necessitates rinsing after each separation, and results in inconveniently increasing the Separatory Funnel. the liquid shaken out. This incon

venience is completely obviated by

FIG. 10.

Double Separatory.

use of a double separatory shown by Fig. 10. On opening the cock between the two limbs of the separator, the heavier liquid may be completely withdrawn from the one limb into the other, by inclining the separator or by suction, into the other limb. The convenience of this form of separator manifests itself, for instance, in the possibility of separating the ether layer from the opium extraction in opium assays perfectly-an operation which as conducted under the directions usually prescribed is very difficult to accomplish satisfactorily. By providing two additional borings in the cock the one or the other of the limbs may be emptied through a corresponding opening beneath, but the author considers this additional arrangement unnecessary. Pharm. Ztg., lii (1907), No. 80, 840.

Automatic Filter-funnel.—Convenient Construction for Quantitative Analysis.-H. Leiser has devised the apparatus, shown by Figs. 11 and 12, for automatic filtrations and particularly for washing precipitates in analytical operations, in which he dispenses with the customary double tubesthe one for the exit of the filtering or washing fluid, the other for the admission of air into the supply reservoir. This, instead, is provided with a short, wide, stoppered tube, with a hole in the side, and attached to the neck by means of a bayonet-lock. The glass cock being so constructed internally that, by a simple turn, the hole in the tube may be closed, or opened for the admission of air. The position of the reservoir having been properly adjusted, and the cock turned so as to admit air, the washing proceeds automatically without disturbing the precipitate. Filtration or

washing with hot liquids is readily accomplished by the arrangement as shown by Fig. 12, which requires no further description.-Pharm. Ztg., liii (1907), No. 56, 584; from Ztsch. f. angew. Chem., 1907, No. 24.

Filtration on a Large Scale-Convenient and Economical Apparatus.— Dr. Justin S. Brewer describes a convenient and economical arrangement of apparatus for continuous filtration on a large scale, which is illustrated by Fig. 13, which may prove useful even to pharmacists who are familiar with the principle on which its utility depends. Two sound alcohol barrels are required. As one barrel must be placed exactly over the other a stronger support must be erected for it. The upper barrel must have all bung and vent holes closed, as the barrel must be impervious to air. In one end of this barrel must be made a hole for a large bung or rubber cork. This hole is used for filling the barrel and for admitting a stirrer. The handle of an old broom serves well as the stirrer, and will be all that is required for thorough agitation. Into a suitable hole in the center of the other end of this same barrel must be screwed a twelve-inch length of three-quarter-inch galvanized-iron pipe threaded at each end. The con

nection should be made air-tight and non-leakable by securing it strongly with a leather washer and lock-nut. At the other end of this pipe is to be connected an ordinary three-quarter inch valve or shut off and to this, in turn, two feet more of the same kind of pipe. The top barrel is now ready and should be placed on the upper shelf of the stand as shown in the diagram. Barrel number 2 may have one head removed and should be fitted with a loose cover through the center of which a hole should be bored to accommodate the filter. A faucet may be inserted in the side of this barrel, far down, for convenience in filling bottles direct from the

barrel. The funnel is made from an ordinary five-gallon tin can by removing its bottom. The funnel is to be converted into a filter by cutting a piece of quarter-inch mesh strong galvanized-iron-wire screening to fit into it, this screening to be covered with a layer two inches thick of white filter-mass. This mass must be pressed down firmly and kept in place by another piece of wire mesh on the top. The filter must be adjusted, of course, so that the end of the delivery pipe from the upper barrel will be about one inch above the top of the layer of filter-mass. A cover should be fitted on the top of funnel. To use, close the valve and fill the upper barrel with the preparation to be filtered; insert the bung or cork

so that no air can enter the barrel; open the valve and let the filtration proceed, taking care that the liquid passes bright and clear. Drugg, Circ., April, 1908, 153-154.

Cellulose Filters-Construction for Large Operations.-The "Oil Paint and Drug Reporter" gives the following general directions for constructing a filter for continuous operations on a large scale: The filtering medium is the cellulose known in commerce as 66 filter wool," which is prepared for use by tearing it into small pieces, moistening so as to form a kind of pap, submitting this to boiling by means of steam, and washing on a sieve of very fine meshes. The washed cellulose is introduced into a cylindrical vessel, open at top, fitted at the bottom with an exit tube, and containing a double perforated bottom, on which is a sieve formed of canvas, and stretched on a hoop of iron. The prepared filtering wool, mixed with water, is poured on this sieve, care being taken to obtain as equal a distribution as possible. The tap of the exit tube is opened, the water flows through, and the filtering wool is deposited on the sieve in a uniform layer of from ten to twenty centimeters. The deposit is covered by another sieve, formed like the first, of canvas, stretched over a hoop of iron wire. When the hoop is not exactly fitted to the inside wall of the filter, it is necessary to stop the spaces, with parchment, for instance, in order that the filtering layer, which tends to become diluted and consequently swelled under the action of the filtering liquids, may not mount again, through interstices, above the upper sieve. The filter is then ready for use.Midland Drugg., Aug., 1907, 1059.

Filter Papers-Kinds Suitable and Required for Different Pharmaceutical Operations.-Professor Wilbur L. Scoville, who may be accepted as an authority on the subject, speaking of "Filtering and Filter Papers," recommends the following qualities of papers most useful for different pharmaceutical filtrations:

For alcoholic liquids, a thin and rapidly-acting filter paper is needed, that material loss by absorption or evaporation may be avoided.

For eye-waters, etc., there should be used a firm paper, that will not give off any fuzz or fibers to the liquid, and that will hold back any fine precipitate.

For syrupy and slimy liquids a thick and soft filter is needed-one that will not clog easily, and will work rapidly.

For thick syrups, oils, etc., a still thicker but firm paper is required. Special work may call for very close filters, that will hold back the finest of precipitates, or the faintest turbidity, but other clarifying agents can be made to accomplish the same result in special cases at the cost of a small waste of the fluid.

These few kinds of filter-papers should be kept in stock, in needed. sizes. They are easily obtained, and are economical.-Drugg. Circ., July. 1907, 458.