so as not to generate too much carbonic acid. Both it and oxygen are of primary importance in asphyxia. In chemical character and physiological influence they are the direct opposites and natural antidotes to narcotizing agents and asphyxiated conditions. They should always be employed whenever practicable, as either alone or in combination with heat they will often save life, even in apparently hopeless cases."

Directions for setting up.

Place the holder in a level position, and fill it with water to within an inch or two of the lower edge of the taper rim.

A piece of lime the size of an egg will help to keep the water pure. Now open all the spigots, especially the one in the top of the receiver, and gently sink it into the water; then close the spigot in the top of the receiver and that on the upper edge of the holder, and arrange the weights that are attached to the receiver.

Put into the first jar (No. 1) about a pint of water. Into the second jar (No. 2) such an amount of water that the long pipe attached to the lid shall dip about one inch below its level; then add a half teaspoonful of sulphuric acid (oil of vitriol) and about a quarter pound sulphate of iron (copperas). Into the third jar (No. 3) put a like quantity of water, and add a couple of sticks of caustic potash.

Arrange the jars in line and connect them by tubing, as shown in the cut. The tube from the retort must connect with the LONG pipe of jar No. 1, and so on. When properly arranged, a current of air blown into

the tube intended to connect with the retort will cause the water to bubble in jars Nos. 2 and 3, and if the spigot to which No. 3 is attached be open, the receiver will begin to rise.

Put into the retort the quantity of [nitrate of] ammonia intended to be used (1 lb. will make about 30 gallons of gas).

Place the sand-dish upon the stove, with sand sufficient to protect the retort. Connect the long pipe of the first jar to the retort by rubber tubing, so that the condensed steam may run into it.

Now apply the heat gradually, and watch the process, being careful not to overheat the ammonia [salt].

The heat should be shut off before the [nitrate of] ammonia is quite all decomposed, in order to avoid breaking the retort; and before the gas has quite ceased to come over, the retort should be disconnected from the first jar, and the receiving spigot closed. This is an essential point, for if not attended to promptly, and the atmospheric pressure thus equalized, the solutions will be forced from one jar to another and into the retort, in consequence of the partial vacuum created by the withdrawal of the heat.

It will be understood that the first jar is merely to receive the drip; the use of the water is simply to keep the jar cool, and the tendency to become overheated may be obviated by setting it in a vessel of cold water. Fresh water may be substituted at each operation.

The solution of copperas should be renewed when it loses its green color, and the potash solution when it loses its alkalinity, as shown by its not turning red test-paper blue.

The inhaling tube is attached to the top spigot of the holder.

'The register indicates the number of gallons of gas in the holder, as well as the quantity inhaled.

If by accident water should get into the pipe by which the gas enters the receiver, it can be drawn off by the little screw-plug at the bottom of the holder.

EFFECTS OF LIGHTNING.

M. Becquerel related to the Academy the fact that during the violent storm of June 21, a workman who was at some distance from the point struck by the lightning, underwent a violent shock, from the effects of which he did not recover for two days. All the nails were torn out from the sole of one of his boots, which M. Becquerel exhibited as a proof of the occurrence. Several academicians cited similar facts, and, among others, M. E. de Beaumont an instance of where the nails were torn out from the butt-ends of muskets. M. Morin also alluded to a pile of balls placed near a powder depot that was overturned two successive days during two storms which destroyed the lightning conductor. Marshall Vaillant also mentioned the case of a man struck by lightning, one of whose shoes, picked up at a great distance, was found to have had all its nails drawn.-Med. Times and Gaz., July 11, 1868, in Medical News.

LIQUID NITROUS OXIDE GAS.

Nitrous oxide gas for anæsthetic purposes has been obtained in a new form. Dr. Evans, of Paris, who was one of the first experimenters with the gas, has brought over nitrous oxide. liquefied by the combined agency of compression and cold. The liquid nitrous oxide is contained in an hermetically sealed vessel, in shape something like a small cannon, made of gun metal. On turning a tap the fluid escapes, and immediately volatilizes with intense cold. For anesthetic purposes it may be conveniently received in a "Clover's bag." The gas thus liberated has been administered by Mr. Clover in four dental cases, and in a case of strabismus operated on by Mr. Haynes Walton. Mr. Clover informs us that he still retains his confidence in the safety of this agent. He has now given it in two hundred and fifty cases without the slightest misadventure, and he has no reason to regard it as specially dangerous.—Med. Times and Gaz. July 11, 1868, in Medical News.

WELL'S PROCESS FOR COPPER-PLATING IRON.

The

This process yields a coating of copper of great brightness and strong cohesion. The object, whether of cast or wrought iron, is freed from rust by immersion for from five to ten minutes in dilute muriatic acid (2 in 100 water) and subsequent scrubbing for a quarter hour with a wire brush and sand, then washing in water until all traces of acid are removed. It is then covered with zinc-wire in spiral turns of about six inches from each other, which also serves as a means of suspension. bath consists of a solution of caustic soda (8 p. c.) of which 11 quarts are mixed with 50 ounces of Rochelle salts and 12 of blue vitriol, making a liquid of a density equal to 19° Beaumé. It retains its activity as long as the copper is kept replaced, and deposition from it proceeds with great regularity. The material of the vessel is best when made of wood, lined with gutta percha and covered with a wooden lid.

When the coating is of sufficient thickness, the object is removed from the bath, first washed with water slightly acidified with sulphuric acid, and then with pure water until the disappearance of all traces of acid; after this it passes into a drying room heated to 132° F. The bronzing, when required, is obtained by a bath of sulphide of sodium, or by means of the same bath as above, somewhat modified, that is, by increasing the proportion of copper to a threefold, in which case the bath no longer deposits copper, but, to all appearances, bronze.

By reducing the points of contact between the iron and wire, though retaining the spiral turns at uniform distances, the deposit gradually assumes a number of colors in the following series, viz.: orange, silver-white, pale yellow, golden yellow, carmine, green, brown, and dark bronze.

As soon as the desired color is attained, the object is washed in warm water, and again dried at 132° F. Between each subsequent change of color is an interval of about five minutes. The reaction is more decided when the alkaline reaction of the bath is stronger.

For in-door work or ornaments the time of immersion may vary from 3 to 72 hours; for out-door objects a much longer

time would be necessary, as many as three to four weeks in some cases. To avoid the tediousness of this operation, the immersion in the alkaline bath is only continued for 12 to 18 hours, but after washing in warm water the coated objects are then placed for 12 or 24 hours in an ordinary solution of blue vitriol, which will increase the deposit quite as uniformly, but much more rapidly. In this manner a coating up to one-fifth millimetre in depth may be formed, which is sufficient for out-door work, and even exposure to water.-Kuhnheim, Druggists' Circular, Aug., 1868, from Dingler's Journal, vol. 188, p. 286.

A NEW METHOD FOR GILDING COPPER WIRE

Has been invented by Mr. Hélouis (36 rue Meslay, Paris) by which the blackening so common with ordinary gilding is prevented. It is partly the same plan as that by which platinum or gold-wire of extreme tenuity has been made, i. e., by enclosing these metals within a cylinder of silver or copper, and draw. ing them out together to a fine degree of fineness, when on treatment of the wire with dilute nitric acid, the outer coating is dissolved, leaving a continuous thread of the metal not affected by the acid. In the present case, however, the purpose is to coat the copper-wire with a thin film of platinum, upon which gold may then be deposited without danger of its subsequent blackening, as generally happens when deposited upon copper or even silver, and the object is accomplished by enclosing the cylinder of copper in a heated ring of platinum, which latter, on cooling, contracts and firmly attaches itself to the inner cone; then the drawing-out process proceeds as usual, the resulting copper-wire being coated uniformly with a thin layer of plati num, upon which the gold may be readily and permanently deposited. This process is also more profitable, because the scraps, etc., of wire, which accumulate in working it, are valuable enough to be collected for the purpose of recovering the precious metals. Druggists' Circular, Aug., 1868, from Dingler's Journal, June, 1868.