as a check to the Arabs, who now make frequent raids across the chott region, retreating afterwards with impunity to the south.

To compensate the loss by evaporation, it will be necessary to run in 187 cubic metres of water per second. The cuttings will be soft earth, and the price per cubic metre would be 50 centimes; a canal of small dimensions would be first dug, and this would be subsequently enlarged by the action of the flowing water itself to the required width and depth. The work could be accomplished in two years and a half. The total volume of cuttings would be 260 millions of cubic metres, representing an expense of 130 millions of francs. Remuneration for the outlay would come from grants of adjacent lands, whose fertility would be considerably increased; from the working of the salt deposits; from the fisheries, and from the rights of transit, etc.-Revue industrielle.

JOURNAL OF THE FRANKLIN INSTITUTE.

SEPTEMBER, 1883. The Screw Propeller, by Jas. N. Warrington, M. E.

In Part I. of the paper, the writer aims to present the most advanced views on the subject, with reliable formulæ for design. Remarks on the propeller with guide-blades.

Part II. discusses the problem: given a vessel with a certain resistance; required the most efficient instrument of propulsion. Comparison between the efficiencies of the guide-blade propeller and the common wheel. An original mathematical scheme for the design of a propeller, with a discussion of effi ciency.

Improvements in apparatus for testing boilers.

NOVEMBER, 1883. Technical Training: an address delivered. before the Alumni Association of Lehigh University, by Thomas M. Drown.

"The principal work of a technical school should be the training of young men in accurate habits of thinking and working. Without this training, the graduate is slow to adapt himself to new situations. The student who has been put through a routine course of study, abounding in the use of text-books, and in the solving of many problems, may be fairly informed as to the condition of his profession, and may have acquired good habits of study, and yet be unfit for practical work which involves principles which he has not learned.

"The proper training cannot be given in the class-room, but must be obtained in the laboratories.

"The centre around which should cluster all the teachings of a technical school should be physical and chemical laboratories; and the ruling idea of the school should be experiment and research. The time has fully come for technical schools to take this advanced position in the scientific training of engineers and metallurgists. The development of this school out of the shop has been so gradual that it is somewhat difficult to realize that the differentiation is now complete, and that the methods adapted for industrial schools do not fit the professional school. A great difficulty in teaching a growing science is that what is taught to-day may be obsolete to-morrow. A system of teaching should, therefore, be adopted which shall recognize this growth and be adapted to it; but we need not render unstable the attitude of a student by showing him that the ground on which he stands moves, and that he will be left behind if he does not move with it."

Apparatus for measuring carbon in steel.

A description of an apparatus, giving accurate methods for the estimation of carbon in steel, by Addison B. Clemence.

DECEMBER, 1883. The Cheapest Point of Cut-off, by Prof. Wm. D. Marks.

Experiments upon non-conducting coverings for steam pipes, by Prof. John M. Ordway.

An investigation into the efficiency of the various coverings used to prevent the radiation of heat from steam-pipes. Over fifty different coverings were tested, and the results show that simple hair-felt with a cover of cheap burlap proved the most efficient. It also appeared that, of the whole number tried, seventeen owed their efficiency to the hair. Asbestos is commonly supposed to have wonderful virtue in resisting heat, but it is a non-conductor only when it is in a light, downy condition and full of air. The experiments with hardpressed asbestos paper show that it conducts heat very readily, and, in cases where asbestos paper was placed between the pipe and the hair-felt, the asbestos failed to prevent the scorching of the hair.

Pressures Attainable by the Use of the Drop Press, by Robert H. Thurston.

A paper read before the American Society of Mechanical Engineers on the magnitude of the pressures attainable in the use of the "drop press," employed in the process of "drop" forging, in the manufacture of small parts of firearms and light machinery.

A New Valve-Motion, by Carl Angstrom.

This valve-motion belongs to the same type as those of Brown, Marshall, and Joy, known by the name of "radial valve-motions." In a radial valve-motion, the motion is usually accomplished by an arm, two points of which move in different curves. One point moves in a closed curve, such as a circle or an ellipse, the motion being derived from an eccentric crank, or from the connecting-rod. The other point moves in either an open or a closed curve, and the motion is accomplished either by levers or slides, or by both combined. In the valve-motion under discussion, the chief distinguishing peculiarity is the mechanism for giving motion to the last-mentioned point of the valve-actuating

arm.

JANUARY, 1884. Note on the losses per horse-power per hour, by condensation of the steam in pipes and cylinders of steam engines, by Professor Wm. D. Marks.

Water-line Defence and Gun-Shields for Cruisers, by P. A. Engineer N. B. Clark, U. S. N.

This paper, originally published in Vol. IX., No. V., Proceedings of the United States Naval Institute, has been revised and enlarged by the author, to correct certain statements made by Lieutenant Very (in "The Development of Armor for Naval Use") in regard to the curved shield, which statements are claimed to be erroneous.

Economy of the Compound Engine, by Professor Wm. D. Marks.

JOURNAL OF THE MILITARY SERVICE INSTITUTION OF THE UNITED STATES.

VOL. IV., No. XVI., DECEMBER. How Early Did War Become an Art? By Captain R. M. Potter, U. S. A.

JOURNAL OF THE ROYAL UNITED SERVICE INSTITUTION.

No. CXXI. On masting of ships-of-war, and the necessity of still employing sail-power in ocean-going ships.

In this paper, Captain G. H. Noel, R. N., argues in favor of masted vessels as being more able to make extended cruises, and to perform the various duties of fighting ships, than the mastless vessels that form part of the naval force of England. Several improvements in the rigs of vessels are suggested: steel telescopic masts; steel tops and crosstrees; cap backstays, coming down amidships, instead of the ordinary backstays; slinging lower yards to saddles working horizontally on the lower masts-these last two improvements allowing sharper bracing of the lower yards.

Machine-Guns, by Captain Lord Charles Beresford, R. N.

Containing a description of the relative merits of different machine-guns. The great value of the machine shell-gun. French capture of Sfax. Tables are given containing the number of Nordenfeldt and Hotchkiss guns in use in the naval services of the principal powers of the world.

MÉMOIRES DE LA SOCIÉTÉ DES INGÉNIEURS CIVILS.

JULY, 1883. Note on the Interior Sea (Tunis), by M. A. Hauet. Two commissions have had this subject under consideration; one, an official board composed of senators, deputies, naval officers, diplomats, financiers, civil and military engineers; the other, self-constituted, composed of projectors and civil engineers. The official commission is of the opinion "that there is not sufficient reason to justify the French government in encouraging the enter prise."

M. Hauet argues at length against the feasibility and propriety of the scheme of attempting to create an inland sea, as proposed by the second commission.

MITTHEILUNGEN A. D. GEBIETE D. SEEWESENS.

VOL. XI., Nos. VII., VIII., 1883. Hotchkiss and Nordenfeldt guns, by J. Schwarz, Austrian Marine Artillery.

Describing the changes and additions made during the past year; with tables, giving weights of guns, projectiles, charges, initial velocity, force of impact, etc.

Kapeller's Deep-Sea Thermometer, by Professors Wolf and Luksch.

The reservoir of mercury is protected from bathic pressures by a vessel of mercury surrounded by a layer of copper filings. Between four and five minutes is given as the time required for the thermometer to give a reliable reading. Other deep-sea thermometers require as much as twelve minutes.

Description, with plates, of boat rigs in the Netherlands navy. The methods of determining the time of true noon, by equal altitudes of the sun, in the 18th century. New ships for the Brazilian navy. Launch of the Chilian cruiser Esmeralda. The Haytian navy. Deepsea soundings (U. S. S. Enterprise, Commander Barker).

A list of fifty-three soundings between Cape de Verde and the Cape of Good Hope.

Project for the erection of lights and electric signal stations in mid

ocean.

VOL. XI., Nos. IX., X. Tables for the reduction of observations of wave-flow, by Professors Luksch and Wolf. Return of the Austrian Arctic expedition from Jan Mayen Land.

An account of the wintering on Jan Mayen, from July, 1882, to July, 1883. The station was one of those provided for by the International Polar Com

mission. Interesting details are given of the climatic and meteorological conditions of the island.

Coast defence of Russia.

Howaldt's plate-bending machine.
French armored ships of the first-class. The Belleville boiler.

VOL. XI., No. XI. The position of the merchant marine in time of war. The ocean currents of the South Atlantic. The Russian use of torpedo-boats. McEvoy's one-wire system for submarine mines (trans.). Stilling waves by means of oil (trans.). Collation of observations upon the heating power and other properties of various kinds of coal. Submarine locomotion.

PROCEEDINGS OF THE INSTITUTE OF CIVIL ENGINEERS (LONDON).

1882-3, PART IV. Raising the S. S. Astral.

The Astral is the largest vessel of the Orient Steam Navigation Company's line of steamers trading between London and Australia. Her dimensions are length 455 ft., breadth 48 ft., depth of hold 37 ft., gross tonnage 5588.

The Astral while coaling in Neutral Bay, Port Jackson, Sydney, filled and sank. Her lower coal-ports were open, and she was taking in coal on the starboard side; the water ballast, provided for ensuring stability at such times, had been removed from the double bottom; as the coaling proceeded, the side of the vessel gradually went lower till some of the port-sills were brought under water, of which a great quantity poured into the hold. The Astral went down stern first in about 52 feet depth of water at the stern, and rather less forward, settling with a list of 11° to starboard. At the time of going down, 200 tons of iron and 1500 tons of coal were on board.

To raise the vessel, a coffer-dam was constructed 410 ft. long, 30 ft. deep, and furnished with a central transverse bulkhead. The coffer-dam was made on shore in completed sections, each 16 feet in length. These sections were weighted, lowered into position, and attached to the vessel by bolts passing through the side-lights. Instead of caulking, canvas was used to make watertight joints; this was tacked on with sufficient slack to allow for contraction. The amount of canvas covering was 26,000 square feet.

Steam pumps were set to work on the 27th of February, and on the 1st of March the vessel, having risen and righted sufficiently, was taken in tow to shallow water and grounded on the top of flood-tide. As the tide ebbed, the coffer-dam was removed. Pumping was then continued, and the vessel was in due course of time trimmed preparatory to going into dock.

This method can of course be most successfully applied in comparatively sheltered situations.

RIGS OF VESSELS, by Captain R. B. Forbes.

In his pamphlet on the rigs of vessels, Captain Forbes gives in an entertaining manner some personal reminiscences, and argues in favor of several radical changes in the rigs of deep-water ships and coasters.

RIVISTA MARITTIMA.

OCTOBER, 1883. Naval appropriations. Collisions at sea. The battle of Port Said; a story of the future (trans.). Our prospective dockyards. The new cruisers of the United States (trans.). The Chilian Navy. Sailing vessels for instruction. International rules to prevent collisions at sea.

NOVEMBER, 1883. Naval appropriations. The disasters at Ischia and Giava. Polar expedition of the Dijmphna. The battle of Port Said (continuation). Strength of the French fleet. Application of electricity on board vessels-of-war. Improvised life-buoys and liferafts.

SCIENTIFIC PROCEEDINGS OF THE OHIO MECHANICS' INSTI TUTE.

SEPTEMBER, 1883. Mechanical Notes, by Harry M. Lane. 1. Friction of slide valves. 2. The slide valve as a water relief valve.

3. Compression and cushion.

Note on the Purification of Drinking Water. By Dr. F. Roeder.

TRANSACTIONS OF THE AMERICAN INSTITUTE OF MINING ENGINEERS.

OCTOBER, 1883. Papers read at the Troy meeting. The colorimetric determination of combined carbon in steel. Roessler's method of manufacturing sulphuric acid and sulphate of copper.

TRANSACTIONS OF THE AMERICAN SOCIETY OF CIVIL ENGINEERS.

VOL. XII., Nos. CCLXI., CCLXII. On the current-meter, showing the reason why the maximum velocity of water flowing in open channels is below the surface. With plates and diagrams.

No. CCLXIII. Paper on the rebuilding of the Monongahela bridge at Pittsburgh, Pa. With plates and diagrams.

TRANSACTIONS OF THE NORTH OF ENGLAND INSTITUTE OF MINING AND MECHANICAL ENGINEERS.

DECEMBER, 1882. The Channel tunnel.

Mr. Charles Tylden-Wright, F. G. S., after a visit to the experimental works at Dover and Saugatte, gives an interesting description of the progress made in the trial-heading, which, on the English side, has been carried 2030 yards under the sea. It is proposed to carry the tunnel through the gray chalk stratum, at a depth of not less than 150 feet below the bed of the sea; and it is confidently expected that the number of "breaks" in this stratum will be inconsiderable for the whole distance between the English and French coasts.

The tunnel can be finished in four years, at the longest (according to Sir Edward Watkin, in charge of the experimental work), and at a cost of £3,000,000.

Arguments are brought forward in favor of two tunnels, as lessening the inconvenience attendant on accidents; and the author takes ground in favor of compressed-air locomotives for hauling débris, and for permanent traffic.

THE UNITED SERVICE GAZETTE.

NOVEMBER 24, 1883. Liardet's detaching and attaching gear for ships' boats.

The apparatus consists of tumbling blocks in the bow and stern of the boat. "The advantages claimed by the patentee of this gear are as follows: Simplicity