been from time to time practiced from the early part of this century; thus, in the Encyclopædia Britannica, Edinburgh, 1815, is found an account of experiments made by Count Rumford. He used oil of turpentine, quicksilver, salt of tartar, sal ammoniac and brass filings, with this object. In Cutbush's Pyrotechny, Philadelphia, 1825, p. 140, we find: Quicklime is said to increase the force of powder. Dr. Baine says that three ounces of pulverized quicklime being added to one pound of gunpowder, its force will be augmented one-third. M. Vergnaud, in a work on fulminating powders in 1846, asserts that certain rifle powder consisted of gunpowder mixed with fulminate of mercury. In the Mechanics Magazine, London, 1825, Vol. 3, p. 275, we find a description of experiments with powder mixed with oil, which showed an increase of effect. In Ure's Dictionary, New York, 1853, p. 174, we find admixture of sawdust with gunpowder recommended as increasing its explosive force. In the London Artizan of 1862 we have a description of Mr. Bennet's improved blasting powder, which consisted of a mixture in which lime was added to the usual ingredient of gunpowder. In the American Repertory, New York, 1841, Mr. Mayer proposes admixture of rosin with gunpowder to increase its effect in blasting."

The injunctions against the manufacturers of Neptune and Vulcan powders were granted. The value of this monopoly may be shown as follows: It is claimed that with proper exploders a dynamite composed of 30 per cent. nitro-glycerine and 70 per cent. meal powder will do as much work as a dynamite composed of 75 per cent. of nitroglycerine and 25 per cent. of infusorial silica. The difference in cost may be estimated as follows:

In a previous suit Judge Blatchford issued an injunction against the manufacture of the following powders:

The Popular Science News, James R. Nichols, M. D., editor, 17, 53, May 1883, contains an editorial article entitled, "What is Dynamite?" from which we extract the following as being a good example of popular science. Referring to the recent difficulties in England, Russia, Spain and elsewhere in Europe, it says: "In dynamite we have a pasty black mass, almost perfectly safe to handle, of which enough can be carried in a side pocket to destroy the lives of a hundred men, if favorably situated, or shatter a building nearly as effectively as could be done with half a barrel of gunpowder placed under it.

"What is dynamite? How is it manufactured? We are fully prepared to answer these questions, as we manufactured the first nitro-glycerine ever made in the United States, nearly twenty years ago, and have had some experiences with it not pleasant to recall. Dynamite is simply nitro-glycerine mixed with an adulterant to render it safe to transport. The added ingredient is usually a fine earth of great absorbent capacity. It has been found that the best kind is the earth which good housewives use to polish their silver with, properly called infusorial earth, because it is made up of the fossil remains of minute organisms. Dynamite, then, is a mixture of innocent polishing powder and sweet, bland glycerine, after it has been acted upon by nitric acid. There is nothing apparently very frightful in this mixture. We can eat glycerine on our puddings and griddle-cakes and grow fat upon it; and a box of silver polish in the house is as harmless as a cake of soap.

"In what has been stated, a strange law of chemical combination comes into view, a law by which, a vast change is produced in innocent bodies by a slight disturbance of their molecular constitution. We disturb the molecular constitution of glycerine by subjecting it to the action of nitric acid, by which nitrogen becomes a constituent of the body, and its whole chemical nature and relationship are changed.

"The dull, stupid nitrogen which exists so abundantly in the air, and which we breathe into our lungs every moment, day and night, becomes the agent which confers upon glycerine the most terrific powers possessed by any agent, save two, known to man. Does not this fact teach an impressive lesson as to the mystery of the forces of nature, and of man's capability of bringing them into action, and we may say, into subjection? If such facts do not cause a feeling of respect for chemical science, it is difficult to conceive of any that will.

"In the manufacture of nitro-glycerine we simply mix with pure glycerine a certain proportion of sulphuric and nitric acids and stir the mixture until the reactions occur, which is in about twenty minutes. The vessels must be placed in freezing mixtures, for if at any time the temperature rises above 32° F. decomposition occurs, and if there is no explosion the whole mass goes off in a vast cloud of nitrous acid vapors which are troublesome and dangerous.

"We never ventured to act upon more than one hundred grains of glycerine at a time, and with this small amount the danger was great and accidents were not a few.

"Our method was to arrange upon a shelf, in a refrigerating mixture, twelve beaker glasses, each containing one hundred grains of glycerine, and into each of them the mixed acids were slowly allowed to enter, the thermometer being anxiously watched all the time. If the heat from the reactions rose above 32° in any glass, away would go the contents, filling the laboratory so densely with red fumes that no object could be seen six feet distant.

"It was regarded as a successful experiment if we saved four glasses out of the dozen. Whilst at present the methods of production are not different, the apparatus and appliances are greatly improved. It must be remembered that we were pioneers in the dangerous manufacture, and but little of the product was needed in medicine and the arts. Now the consumption is enormous, and large manufactories are established in many sections of the country. The United States government chemists make the best nitro-glycerine at the laboratory at Newport, Rhode Island. It is used largely for filling torpedoes. "In what has been said we have endeavored to afford a popular view of the chemistry of dynamite. It does not explode at the touch of fire, as does gunpowder, but it must have brought to bear upon it, or in contact with it, another explosive agent, a fulminate. A fulminate of mercury is better than a fulminate of silver, for the rhythm of

its detonation is more in accord with that of dynamite. Dynamite detonates, and does not explode as does gunpowder. Its action is so much quicker than the movement of air that it strikes against a column of air with the same force as a hammer falling upon a blacksmith's anvil."

The following books may be of interest to students of explosives: Die Grundsätze der Thermochemie. Dr. Hans Jahn. Vienna, 1882. Alfred Holder, 8vo, 238 pp.

Thermochemische Untersuchungen.

Julius Thomsen. Vol. I.

Neutralization und verwandte Phenomena, 449 pp.

loide, 506 pp. Leipzig, 1882. J. A. Barth.

Vol. II. Metal

Lehr- und Handbuch der Thermochemie. Dr. Alex. Naumann. Brunswick, 1882, F. Vieweg und Sohn. 606 pp.

The Explosive Art, 1875, and the Orders in Council of April 20, 1883, their Prejudicial Effect on Mining and Quarrying, and the Encouragement they give to Fenians. London, 1883, A. P. Blundell & Co.