acetylene, under normal atmospheric pressure, gives 896 liters of gas.

Annexed is a drawing showing a burner in direct connection with a steel cylinder containing liquid acetylene.

Through this means vehicles and isolated or other buildings can be lighted with a bright and quiet flame for a long period of time, as 10 liters (10.5 quarts) of liquid acetylene are equal to 3,600 liters (3} cubic meters) of gas, which represents 3,600+10=5.700 normal candlepower hours.

Another advantage of this gas, as shown by A. Frank (Vortrag im Verein z. Beförder des Gewerbefleisses, February, 1895) is that for the manufacture of 1,000 kilograms (2,204.6 pounds) of calcium carbide (steam power to run dynamos) 3,400 kilograms (7.495 pounds) of middle-grade coal is necessary, while, on the other hand, three times that amount of coal is required to produce the same amount of candlepower with the common illuminating gas.

Acetylene gas explodes strongest when mixed with air in the ratio of 1 volume gas to 12 volumes air. When mixed just in the proportion of 4 to 5, explosion takes place.

Naturally, the fact that acetylene is poisonous demands consideration; but this point appears to be frequently exaggerated. As shown by Frank and Weyl (Ber. d. deutsch. chem. Ges., 1895, p. 2107), mice and rabbits can remain in a 4 per cent acetylene atmosphere without exhibiting any evil effects.

It may also be remarked that this gas should be handled with considerable care in experiments, as its tendency to severe explosions has been but too sady demonstrated on both sides of the Atlantic. To this end, caution should be exercised in the following details:

(1) Copper should not be used on any part of the pipes, cocks, burners, or apparatus, as the contact of acetylene with this metal will shortly be followed by an explosion.

(2) The gas should be under sufficient water pressure to insure proper velocity in its distribution through the pipes; if the pressure is weak, the flame is liable to sink through the burner into the pipe. The result of such an accident will be an explosion.

Acetylene
Liquid

The police authorities of Berlin forbid experiments with this gas. unless permission has previously been obtained. The authorities investigate the apparatus and convince themselves of its perfect safety before issuing the permit.

It would be almost impossible to embody in this report a description of the numerous inventions that have been made in European countries for the use of acetylene gas, and as most of these inventions have already been patented in the United States, I have therefore deemed it proper to omit such a description.

REPORT BY CONSUL-GENERAL MASON.

After a period of experiment and uncertainty, during which it has encountered the more or less active opposition of many persons interested in coal gas and electrical lighting, the system of lighting. by acetylene gas produced from carbide of calcium seems to have been definitely accepted by scientists as technically feasible, and, under properly regulated conditions, safe and economically advantageous.

The result has been to greatly increase the use of carbides during the past six months, so that for the moment the demand has nearly overtaken the European supply, and it is credibly reported that a company in Belgium has recently closed a contract for a large quantity from the works at Niagara Falls, in the United States. Hitherto the main source of supply for Germany and eastern Europe has been the Aluminium-Industrie-Actien-Gesellschaft, at Neuhausen-on-Rhine, near the Falls of Schaffhausen, which was the first establishment, except one in France, to begin the manufacture of carbides on a large scale by means of electrical heat generated through water power.

This company supplies about 60,000 kilograms (132,276 pounds) of carbide annually to the Prussian State railways, where it is used to purify and enrich oil gas for the illumination of railway cars, as well as stations, shops, and other buildings. Having control of practically unlimited water power, the company at Neuhausen is steadily enlarging its capacity, and now offers for export carbide of standard quality, capable of producing from 300 to 320 liters of acetylene gas per kilogram, subject to the following prices and conditions. Lots of 1 to 1,000 kilograms, 60 centimes per kilogram=$115.80 per metric ton (2,204.6 pounds); lots of 1,000 to 5,000 kilograms, 50 centimes per kilogram=$96.50 per metric ton; lots of 5,000 kilograms or over, 45 centimes per kilogram=$86.85 per metric ton.

These prices are for the carbide alone at the works in Neuhausen. No. 206-2.

It is packed for shipment in tin cans or drums, and these, when sold for export, are again inclosed in wooden cases, and for this the following packing charges must be added to the net rates given above. The cans are of three sizes, containing, respectively, 12, 50, or 180 kilograms, equal to 26, 110, and 396 pounds avoirdupois, and are charged to the purchaser of carbide at 15 cents, 58 cents, or $1.25 each, according to size. For the wooden cases in which the cans are packed, the charges range from 10 cents per small can to 20 cents for the large ones, so that the whole cost for hermetically sealed tin drums and wooden casings would be not far from $15.75 per ton of carbide.

These are, so far as can be ascertained, the minimum prices at which carbide can now be obtained in this country, where it is manufactured by the most economical method of smelting together lime and carbon by electrical heat generated by water power. The only other competitor in the German field is a factory at Bitterfeld, in Prussian Saxony, where about 10,000 kilograms are produced annually with electric heat generated by steam power, whereby the cost is so increased that carbides from Bitterfeld are sold at 80 marks per 100 kilograms, equal to $190.40 per metric ton.

The strong and increasing demand for the new material is naturally a potent stimulant to inventors and capitalists, and one hears frequently of newly invented processes for the production of carbides by original and cheaper methods, as well as of the construction of new plants which will employ machinery and processes similar to those already in use. Of these new enterprises, the most important appears to be a laboratory now in construction in Canton Glarus, Switzerland, where water power to the extent of 4,000 horsepower will be employed. These works are intended to be ready for operation early next spring, and are expected to furnish a large and constant supply of carbide at from $60 to $70 per metric ton.

Of the new systems or processes of manufacture, one of the most interesting and important is that invented by Mr. Emil Walther, of Saxony, and described in a report by United States Consul Sawter, at Glauchau, published in CONSULAR REPORTS No. 198 (March, 1897), pp. 420-422. By this method carbides are said to be produced by smelting together carbon and alkaline earths in a furnace heated, not by electrical current, but by darting flames of acetylene gas intensified by pressure, whereby the high temperature required to combine the carbon and calcium can be generated on a large scale and more cheaply than by electricity. As to the practical efficiency of this method, no positive information can be obtained at this distance; but it is regarded by disinterested experts as perhaps the most promising of the various new processes that have been an

nounced, concerning all of which judgment will be suspended until their practical efficiency shall have been demonstrated.

The economics of acetylene gas for domestic lighting under the conditions now exising in Germany may be stated as follows: One kilogram (2.2046 pounds) of calcium carbide yields, according to purity, from 300 to 320 liters of acetylene gas, having, volume for volume, fifteen times the illuminating power of good ordinary coal gas. Το produce 1 cubic meter (35.31 cubic feet) of acetylene gas requires 7.04 pounds of carbide, costing, in ordinary quantities, say, 40 cents. Since the illuminating power of acetylene gas is fifteenfold greater than that of coal gas, this 1 cubic meter would be equal to 15 meters (529.65 cubic feet) of ordinary gas, which, at the present price of gas in Frankfort, would cost $1.35. The saving effected would therefore be, theoretically, the difference between 40 cents and $1.35, or 95 cents. This is perhaps an extreme statement, since coal gas is supplied at some other places in Germany as low as 5 cents per cubic meter-about $1.40 per 1,000 cubic feet. Even then, the cost of acetylene, as compared with coal gas, would be as 1.6 to 3—an economy of nearly 100 per cent. From the best information that can be obtained, an acetylene-gas flame of 30 candlepower consumes 20 liters of gas and costs three-fourths of a cent per hour. This contemplates the use of carbide of standard purity and productive power, and, in this respect, the carbides of commerce vary considerably.

In a series of tests made in Switzerland and reported in the Swiss Builders' Gazette, the cost of carbide from the works at Neuhausen is given at 400 francs ($76.30) per ton, but as it yielded only 280 liters of gas per kilogram, this would make the cost of acetylene 32 cents per cubic meter, instead of 40 cents, as contemplated in the foregoing calculation, which is the rate estimated for small acetylenegas plants, such as are used for lighting villas and detached hotels or other buildings. In France, it appears from the report of tests made by the Eastern Railway Company, the cost of carbide is reckoned at $107 per ton, but it is of standard purity and yields 300 liters of gas per kilogram.

Into the much-discussed and still hardly settled question of the safety of acetylene gas as compared with petroleum, electricity, and other illuminants for popular use, it is not the purpose of this report to enter. This phase of the subject has attracted great attention in Germany, where police regulations extend to the minutest details of everything that concerns the public safety or health.

Expert opinion in this country seems agreed upon the proposition that, with reasonable precaution to secure purity in the carbide and properly constructed apparatus, its use may be rendered quite as

safe as that of petroleum lamps, high-tension electrical conductors, steam boilers, liquid carbonic acid, and other things that are used constantly without a thought of the danger which they involve. There should be regulations, of course; but they need not be more stringent than those which govern the use of steam and electricity in cities.

From the reports presented at a recent meeting of the Chemical Industrial Association, at Berlin, it would appear that most of the danger attaching to acetylene belongs to its liquid form. Mingled with atmospheric air, pure acetylene is less poisonous than coal gas. But in, the present stage of carbide manufacture, it often contains impurities which, in contact with water, develop phosphureted, sulphureted, and even arseniureted hydrogens, which are not only deleterious when inhaled, but in contact with copper produce gaseous compounds that greatly increase the danger of explosion under pressure. These can, however, be almost wholly removed by passing the acetylene gas through an acid solution of a metallic salt.

But the principal peril is encountered when, for convenience of transportation or other reason, acetylene gas is condensed into liquid form. This may be done by a pressure of 68 atmospheres at any temperature below 98.7° F., which is considerably less than the pressure and cold required to condense carbonic-acid gas. Acetylene so liquefied has a tendency to explode into carbon and hydrogen, with an intense development of heat, and under these circumstances is unmanageable by any means that have yet been devised. Liquefied acetylene will probably sometime be as safe and common a material as liquid carbonic acid, but it is not so now, and until it is better understood and mastered, calcium carbide will doubtless continue to be its safest and most convenient vehicle.

PRICE LIST FOR CALCIUM CARBIDE.

In lots of 1 to 1,000 kilograms, 60 centimes per kilogram; 1,000 to 5,000 kilograms, 50 centimes per kilogram; 5,000 kilograms and more, 45 centimes per kilogram-delivered in Neuhausen, payable in advance at the receipt of our invoice, packing extra.

The carbide is packed up either in hermetically soldered tin-plate boxes containing about 8 to 12 kilograms (less we do not sell) or in tin-plate casks containing about 50 and about 180 kilograms each.

For the boxes, we charge 75 centimes; for the small casks, 3 francs; and for the large ones, 6.50 francs per piece. The packing of the boxes into wooden cases is to be paid extra, while the casks are enveloped with wood at I franc each for the large ones and 50 centimes for the small.

ALUMINIUM-INDUSTRIE-ACTIEN-GESELLSCHAFT,

Neuhausen, Switzerland, May 22, 1897.