FIG. 29.

pear opaque under the microscope or that are themselves too deeply colored are excluded, as well as those which possess indices of refraction greater than that of oil of cassia, which, with the exception of bisulphide of carbon, possesses the highest refractive power of any liquid. For the details of this very interesting paper the reader is referred to "Phar. Jour. Trans.," December 24th, 1881, pp. 522524; from "Ann. d. Physik u. Chemie," XI., p. 722.

Colorimeter-Simple Construction.-Dr. H. Hager proposes the following simple colorimeter. A cylinder, b (Fig. 29), is made of black or dark-colored paper, into which two test-tubes that are equal in width and glass can be inserted, as shown at b, c, c. The tubes are partly filled with the liquid to be tested, so that the line part can be compared against the light. It is necessary that the tubes lie closely together. The tube containing the normal liquid has the mark O on its surface, and that with the liquid to be tested the sign +. The application of the instrument is apparent. -Oil and Drug News, April 4th, 1882, p. 6.

Apparatus for Separating Ether from Watery Layers, etc.-See Ether, under "Organic Chemistry."

Colorimeter,

Apparatus for Observing the Color of Water.-See Pure Water, under "Inorganic Chemistry."

Apparatus for Estimating Carbonic Acid.-See Carbonic Acid, under "Inorganic Chemistry."

Apparatus for the Determination of Ammonia by Distillation.—See Ammonia, under "Inorganic Chemistry."

A Simple Dropper.-A very simple dropper (Fig. 30) may be made by bending a piece of glass rod at a right angle, and drawing one end

FIG. 30.

Dropper.

out to a point. On inserting the other end into the bottle, and gently inclining the latter, some of the liquid will ascend along the tube, even before the liquid in the bottle has reached the mouth, and may be dropped at will.-New Rem., May, 1882, p. 154.

Asbestos Stoppers for combustion-tubes are made by J. Fleming White as follows: The asbestos is separated into fine threads, mois

tened with water, twisted into a plug, crowded into the cylinder of an ordinary steel crusher, such as is used to pulverize minerals for analysis, and compressed by driving the piston of the crusher down upon it with a hammer, or better, by the screw of a vice. The plug is kept under pressure for several hours, then dried within the cylinder upon a sand-bath, pushed out of the cylinder, and after ignition over a blast-lamp is ready for use. In this condition the plug loses no weight under prolonged ignition, is elastic enough to make a tight joint when fitted to a combustion-tube of suitable size, and may be smoothly perforated with an ordinary cork-borer.-Chem. News, August 5th, 1881, p. 65; from Am. Chem. Jour.

Papier-Mache Evaporating-Vessels, etc.-A writer'in "Pharm. Centralh.," speaks highly of evaporating-vessels and funnels made of paper-mass and well varnished. The vessels can be exposed to heat in a water-bath, filled with different liquids, such as water, saline solutions, including a 10 per cent. solution of carbonate of sodium, olive oil, mineral oil, dilute acids, etc., without being thereby affected. Even ether and strong alcohol do not affect the varnish at first, but do so after some time. Caustic alkaline solutions, however, destroy the surface. Exposure to a dry temperature of 160° C. does not change them. They possess the inconvenient property of retaining the odor of essential oils, etc., that have been in contact, but, being, in addition to the abovementioned merits, quite strong and durable, will doubtless find manifold applications in the laboratory.-Pharm. Ztg., No. 84, 1881, p. 630.

Zinc Vessels for Storing Vegetable Substances have been found by Dr. I. Nessler slightly corroded on the inner surface. He draws attention to this so that they may be frequently examined, and recommends that in such cases, the inner surface be coated with a good varnish. The corrosion appears to occur only in certain cases; in the case of most substances it was not noticed.-Arch. d. Pharm., January, 1882, p. 49.

Platinum Vessels-Corrosive Action of the Flame.-See Platinum, under "Inorganic Chemistry."

Platinizing Metallic Vessels. According to Hager, tin, brass, tinned iron and copper vessels may be coated with platinum, by painting their surfaces with a solution of 1 part of chloride of platinum in 15 parts of alcohol and 50 parts of ether, and after drying in a warm place, rubbing them with a linen or woollen cloth until polished. It is necessary that the vessels, before platinizing, shall be perfectly clean and bright. The coating of platinum so produced protects the vessels from the action of acids and alkalies. The coating is readily replaced in defective spots.-Arch. d. Pharm., April, 1882, p. 299, from Phar. Centralh., 1882, No. 8.

Tin-coating in the Cold Way.-J. Zilken communicates the following method of coating with tin in the cold way: The article is thoroughly cleansed, so as to remove fat, etc., first with potash, then with a 15 to 20 per cent. sulphuric acid, rubbed with sand, and finally washed with pure water. It is then immersed in a bath composed of 100 liters water, 200 to 300 grams stannous chloride, 300 grams alum, 450 grams common salt, and 200 grams of cream of tartar. The article, surrounded with strips of zinc, is allowed to remain in the bath for 8 to 10 hours, rinsed, placed into water containing 8 to 10 grams carbonate of magnesium in the liter, dried, and polished with fine sand.-Arch. d. Pharm. Jan., 1882, p. 55, from Dingl. Journ., vol. 249, No. 3.

Labels on Tin.-A very good method of causing labels to adhere to tin is a dilute solution of white gelatin, or, better still, of isinglass. Its strength should not be more than one in twenty, and it may be applied by means of a pencil or sponge. It has this advantage, that labels applied to the surface so covered do not adhere permanently at once, but may be slid about long enough to permit their proper adjustment and straightening.

Other methods are the following: 1. Soften good glue in water, then boil it with strong vinegar, and thicken the liquid, during boi ing, with fine wheat flour, so that a paste results. 2. Starch-paste with which a little Venice turpentine has been incorporated while it was warm. 3. Paint solution of tannin over the spot, let dry, and then affix the label, previously gummed and moistened.-From Phar. Zeitg., in New Rem., October, 1881, p. 293 and 303.

Cement for Mending Pestles.-Mr. Robert F. Fairthorne states that one of the strongest cements, and one that can be readily made, is obtained when equal quantities of gutta-percha and shellac are melted together and well stirred. This is best done in an iron capsule placed on a sand-bath, and heated either over a gas-furnace or on the top of a stove. It is a combination possessing both hardness and toughness, qualities that make it particularly desirable in mending pestles and mortars. When this cement is used the articles to be mended should be warmed to about the melting-point of the mixture, and then retained in proper position until cool, when they are ready for use.-Am. Jour. Phar., August, 1881, p. 396.

B. PREPARATIONS.

AQUE.

Aromatic Waters-Solubility of Carbonic Acid in Them.-See Aquæ, under" Pharmacy."

Elatina-An Italian Substitute for Tar water.-In this preparation, which is largely used in Italy in place of tar-water, Ciutlini gives the

following formula: Green pine cones, 6 kilos; olibanum, 80 gm.; tolu balsam, 50 gm.; Burgundy pitch, 40 gm.; juniper berries, 600 gm. The mixture is macerated over night in sufficient water. Afterwards 12 kilos of distillate are obtained by the aid of a slow fire. The liquid is filtered, bottled, and used in doses of half a tumblerful two or three times a day. Am. Jour. Phar., August, 1881, p. 404; from Phar. Ztg., 1881, p. 285.

Hunyadi Yanos Mineral Water-Preparation Artificially.—An artificial mineral water, which will be found to possess every advantage attributed to the natural water, is made by Professor Charteris by dissolving magnesium sulphate, 514.92 grains; sodium sulphate, 519.54 grains; potassium sulphate, 2.76 grains; sodium chloride, 39.15 grains; and sodium bicarbonate, 15.69 grains; in water, 16 ounces. Dose, 2 ounces and upwards. A product made by following Liebig's analysis was found to be too weak, and did not produce purgative action.-Am. Jour. Phar., June, 1882, p. 310; through Phar. Jour. and Trans., February 25th, p. 703; from Lancet.

CERATA ET UNGUENTA.

Petroleum Ointments-Products Suitable for their Preparation of Different Melting-points.-Mr. S. A. D. Sheppard has visited the oil regions, where facilities were extended to him to make a thorough inquiry into, and examination of, the products that may be suitable for the preparation of petroleum ointments having different melting. points, a very interesting description of which is given. The author arrives at conclusions which he sums up as follows:

Although the term paraffin may be and is properly applied chemically to any one of the long series of hydrocarbons, commencing with marsh gas and running up through the benzins, the illuminating oils, and the lubricating oils, to paraffin wax, the usage of trade really confines the term paraffin to those of the series that are solid or semi-solid at ordinary temperatures. It is in the latter sense that the term will be used in the following remarks.

Petroleum, as it comes from the earth, may be said to be capable of division into three parts by distillation, viz., into what may practically be termed two series of oils: the benzin oils, and the paraffin oils, and paraffin wax.

The division between the two series of oils may be said to occur in the process of distillation when very carefully conducted, when the gravity of the distillate has been reduced to about 42° to 41° Baumé

The benzin oils are colorless or white oils, and have a peculiar benzin odor. They are also said to have a definite boiling-point.

The paraffin oils are yellow or straw-colored oils, and have a greasy or waxy odor.

The oils in the paraffin series are very easily split up into other and lighter products of the same series by the skilful application of heat.

The article desired as a base for ointments by physicians and pharmacists is really amorphous paraffin mixed with a certain amount of one or more of the above-mentioned series of paraffin oils, but entirely free from admixture with any of the benzin series or the crystalline paraffin wax.

The benzin oils, if present, give an objectionable odor, and the crystalline paraffin wax, if present, will, in time, especially if the article be exposed to a low temperature, render it granular and cause it to separate, thus losing that homogeneous character so desirable in an ointment.

The question now is how to obtain this desired article. From all crude petroleum oils paraffin settles to a greater or less degree, so that if a tank containing two hundred and fifty barrels has been used as a well for three or four years, it may be expected to contain at the bottom of the tank a deposit, ranging in depth from four to eight inches, of a mixture containing a large proportion of paraffin. This paraffin is always in an amorphous condition, the crystalline character being found only in those products that have been subjected to the process

of distillation.

Observations show that this amorphous paraffin and the harder varieties that clog the pipes may be easily obtained in quantities sufficient for all the demands of medicine and pharmacy. We have, therefore, ready formed for us in Nature's laboratory, the article we desire, but it is contaminated by oils of the benzin series, with odorous and coloring matter; the oils are gotten rid of by careful distillation, and the other by filtration through animal charcoal.

The harder variety, "rod wax," is the article that may be used to advantage to increase the melting-point of petroleum ointment. Its melting-point being about 140° F., and it being an amorphous and not a crystalline paraffin, it can be mixed, when purified, with goods of a lower melting-point, to make a homogeneous article, as is shown by samples of such mixture that have stood more than a year. It is better, however, that the admixture be made previous to distillation. It is necessary that the animal charcoal, used as a filtering medium, bet freed by recent burning from condensed noxious gases or other impurities.

To obtain petroleum ointment of a desired melting-point, it is necessary to start right; that is, to select such crude material as will, by distillation, or purification in some way, give a residuum having the wished-for melting-point. It is the opinion of the writer that, to ob