reservoir; No. 2 is the percolator; No. 3 is the receiver. The lower orifice of No. 1 is connected with No. 2 by means of a short piece of vulcanized rubber tubing.

The powdered substance to be extracted is introduced into the percolator (No. 2); a plug of tow is inserted in the neck, followed by the cork carrying the glass tube. The bottle is inverted and its contents packed as closely as possible, by gently slapping the sides of the vessel with the hand. The side orifice near the bottom of the percolator is then connected with the reservoir by means of the rubber tube. The reservoir stands on a shelf; the percolator is supported by the rings of a retort stand. The cork of the receiver is first slipped on to the glass tube of the percolator, and then brought down into the neck of the receiver. This cork should have a small escape-hole in it.

If a steady stream of the menstruum is desired, a small piece of glass tube is passed through the cork of No. 1, and connected, by means of rubber hose, with a similar piece through the cork of No. 3. Equilibrium

is thus maintained.-Amer. Jour, Phar., May 1883, 269, from Proc. Cal. Phar. Soc., 1883, 40.

A New Percolator.—Mr. Samuel J. Hinsdale has devised the apparatus for percolation shown by Fig 10, which is intended to be adapted to the

FIG. 10.

Hinsdale's New Percolator.

percolation of tinctures, syrups, extracts, and other fluids.

A cylindrical

chamber, designed to receive the substance to be percolated, is provided near its lower extremity with a strainer and stop-cock. The upper end of this chamber is attachable to an air-chamber above it, the connection being made air-tight by means of screw threads and rubber gaskets. A convex diaphragm with marginal openings is located in the air-chamber near its connection with the cylinder below, and serves to deflect the menstruum when it is poured in through the orifice at the top, thus preventing the disturbance of the contents of the cylinder. Attached by a flexible pipe to the air-chamber is a bulb of rubber provided with valves, by the aid of which the tension of the air in the chamber can be increased, and the operation of percolation hastened.-New Rem., Jan. 1883, 9.

FILTRATION.

Upward Filter-New Construction.—Mr. Charles Symes, in connection with some very interesting remarks on "filtration," " "filtering material," etc., draws attention to an "upward filter" of his construction, which combines upward filtration with the advantages of the motion tube. The apparatus consists of a plain tin cylindrical vessel with a tap-hole 1⁄2 inch from the bottom; it is 22 inches high and 8 inches diameter. A tin tray 7 inches in diameter, with a vertical rim 1 inch or 14 inch deep, has a hole in the rim; this and the hole near the bottom of the cylinder being fitted with a short female screw of the same pitch of thread. Over the tray the filtering material (flannel, calico, paper supported by muslin, or any other that may be suited to the liquid. to be operated on) is tied securely; it is then inverted and placed in the cylinder so that the hole in the rim and the tap-hole are opposite one another. A tap with a bend at a right angle, is screwed in so that it holds the two together and assists a short leg in supporting the tray in position. To the end of the tap is attached an india-rubber, or a long glass tube turned on itself, the latter being attached by means of a short rubber tube. Obviously any communication between the tap and the contents of the vessel must be made through the filtering medium which covers the inverted tray, and any deposition which takes place must be on the bottom of the vessel itself or on the opposite side of the tray, but not on the filtering surface; and herein lies the special advantage of the filter, which is a modification of that constructed by Mr. Wm. R. Warner some years ago for filtering oils.-Phar. Jour. Trans., May 19, 1883, 937-939.

Filtering Apparatus for Syrups, Oils, etc.-The apparatus illustrated in the accompanying cut (Fig. 11) has been devised by Mr. Prikryl, and is intended for filtering syrups, oils, fats, extracts, etc. It is an iron vessel, with acid-proof enamel lining. The upper vessel has an open bottom, over which any straining cloth can be fixed, and is held fast by an India-rubber ring. The capacity of the apparatus described is eight

litres for a, and ten litres for b.-New Rem., Feb. 1883, 50; from Zeitschr. Oest. Apoth. Ver.

Syrup-Filtering Apparatus-Simple Construction.-Mr. Guenske suggests an arrangement for filtering syrups which, he says, leaves nothing to be desired. He takes an ordinary calcined-magnesia bottle, fits its mouth with an India-rubber cork with a double bore, and, as shown in the engraving (Fig. 12), fits a funnel in one of the bores and a glass tube through the other. On the upper end of the glass tube a second small glass tube is connected by an India-rubber tube. Round the lower part of the funnel a piece of wire netting is arranged to support the filter and to prevent it bursting at the point. Then, when the syrup is poured in, and the filter damped all round, the air is sucked from the bottle by the mouth as completely as possible through the tube, and the Indiarubber tube pinched together. The sucking is repeated each time that the syrup is poured into the filter. Mr. Guenske says that by this method he can filter three kilograms of syrup in an afternoon.-New Rem., May 1883, 148, from Chem. and Drugg.

Filtering Apparatus-Simple Construction.-A very simple apparatus for filtering water is that here described (Fig. 13). Take a glass tube about one yard long and of about one-fourth inch bore, and bend it twice at a right angle, as shown in the cut, so that the longer leg is about

six times as long as the shorter. To the shorter leg is fastened, by means of a perforated cork, a wider glass tube, about 434 inches long and about % inch wide (inside); this tube is filled with absorbent cotton (freed from fat), a small piece of perfectly clean sponge being laid next to the cork, and a similar piece being used to close the other opening of the tube. In place of the narrow glass tube, a rubber tube may also be used. The apparatus is started like any other kind of siphon, and will be found to work well in all cases where the liquid is not too much loaded with suspended matters.-New Rem., Feb. 1883, 49.

Asbestos Filter.-Method of making, etc., see Asbestos, under "Inorganic Chemistry."

APPLICATION OF HEAT, ETC.

A New Burner for Heat and Light.-Lewis Jacob has devised a new burner, which is capable of application for a variety of purposes. principle is based on the observation that a mixture of a combustible gas and of air, if somewhat compressed and ignited at the top of a suitable burner within a cage of metallic platinum or other refractory material, raises the metal to a point of incandescence, producing thereby a brilliant light, and, at the same time, an intense degree of heat.

The cap to be attached to the mouth of the burner is best made of platinum gauze or finely perforated sheet platinum. In this case the utmost attainable degree of heat and light results. When the mixture is first ignited, the light is but feeble; but, as soon as the metal begins to become heated, the light increases and finally becomes very brilliant. The combustion, at the same time, is quite perfect, neither smoke nor other disagreeable products making their appearance. The most suitable pressure at which the air should be injected into the gas is about 2 pounds to the square inch. The annexed cuts show the arrangement of the burner, (Fig. 14), the elevation, and (Fig. 15) a section of the same.

Jacob's New Burner for Heat and Light.

a is a cap of fine platinum gauze slipped over the end of the burner. The air or the gas, or both together, may be compressed in the tube a' or

b; if they are compressed in b, their issuing from the orifice will attract an additional current of air from a2.-New Rem., March 1883, 79, from "Il Progresso," Jan. 15, 1883.

Hot-Air Chamber for Pharmaceutical Purposes.-Mr. Thomas Maben draws attention to the hot-air chamber illustrated by Fig. 16, which he

finds admirably adapted for pharmaceutical purposes, and which is a modification of one designed originally by Mr. Hislop, one of his apprentices, who intended to use it for drying photographic gelatin plates. The chamber consists of a strong wooden box (4), 18 inches high by 18 inches wide, and 14 inches deep. The door may be hinged, as shown in the cut, but is more convenient if it is sliding. Wooden supports are fixed to the inner sides for the reception of teak spars serving as supports for trays, dishes, etc. The bottom of the box has a perforation of 3 inches in diameter, into which a zinc cylinder (B) is securely fitted; and to this is soldered the upper end of a copper cone (C) with a flat bottom, while into this latter a bent tube (D), diameter 21⁄2 inches, and 9 inches total length, is securely inserted in the manner shown. A corresponding perforation is made in the top for receiving a tube to answer the purposes of a chimney. The source of heat is a Bunsen burner or spirit lamp ap