Page images
PDF
EPUB
[blocks in formation]

just outside the rim of the excavating wheels. The buckets have a top and back, but no bottom. They are shaped somewhat like the bowl of a dragscraper; and, in fact, they act very much like a drag scraper in digging, for as the excavating wheel revolves, each excavating bucket cuts off a slice of earth which fills the bucket. When the excavating bucket reaches the end of the arc near the top of the wheel, the dirt falls out of the bucket upon a belt conveyor.

This trench excavator cuts the full depth of the trench at one stroke and leaves the bottom exactly in the grade desired. The operator sights along the sight arm at the targets on the flag poles provided, and operates a hand wheel that raises or lowers the excavating wheel until the sight arm is at the proper level. In this way the operator has perfect control over the depth to which the excavating wheel cuts and he can keep the bottom of the wheel within a fraction of

an inch of the desired grade.

By the use of this modern machinery three lineal feet of trench can be dug per minute in ordinary earth a depth of three feet, and at this rate, one machine would dig 180 lineal feet per hour, or 1,800 feet per working day of ten hours.

[graphic]

STEAM DITCH-EXCAVATOR AT WORK.

[blocks in formation]

ENGLISH TORPEDO BOAT. Latest addition to British Navy.

gen produce a gas that necessitates abandoning closed works, such as a mine or tunnel during the explosion, and the laborers cannot return to work for a long time thereafter, depending upon the facility for carrying off the gas. Potasimite is said to produce no noxious gas, the only precaution necessary in its use being that the workmen get out of the way of the flying particles of blasted rock.

and are built diagonally with two wooden skins, with a waterproof skin between them. This boat operates at a uniform speed of sixteen knots per hour, and has maintained a speed on a number of official trials, sufficient to guarantee the quality and design. of the vessel. These pinnaces are equipped with engines of the highest class of torpedo boat machinery. The engines operate at a speed of from 530 to 600 revolutions per minute.

As noted in the illustration, a protected lookout and pilot house is provided in the bow of the pinnace, and the whole boat is well protected so that it can stand the heaviest weather.

[graphic]
[graphic]
[blocks in formation]

STEAMER DEUTSCHLAND.

Electrical Relics

THE HE illustrations show the beginnings of those electrical devices that have revolutionized the mechanical and engineering sciences. From the early dynamo of Faraday have sprung mammoth generators and a multitude of devices to utilize their energy. This inventor by his discovery of the law of induced currents laid the basis of modern electrical science. The Wheatstone bridge rendered possible the comparison of electrical resistances, and Prof. Daniell's loadstone has played also a most important part in scientific progress.

Alcohol Torpedo Boat

TORPEDO boats of a type new to

naval warfare are soon to be manufactured by the International Power Company. The vessels are to be operated by alcohol motors. It is said by naval constructors that the use of alcohol motors will enable the manufacturers to make a torpedo boat of the same length and the same tonnage as any steam-power boat, with a saving of onehalf the weight and one-half the draft.

That saving would be of great advantage. In the first place it will enormously increase the radius of action of the boat. At present, the coal supply will not enable a boat to make a cruise of more than 400 miles without recoaling.

[graphic]

ELECTRICAL RELICS.

In center, Prof. Daniell's lodestone with Faraday's induction coil; in the foreground, the original Wheatstone bridge; on the sides are two of Prof. Henry's original induction coils.

British Cross the Seas AN

N interesting movement in the commercial world is the recent establishment in the United States of branch factories by British concerns. Within the last year there have been four of considerable importance; one for the manufacture of weighing machines, at South Milwaukee; a chemical concern at Niagara Falls; a fancy cotton goods mill at South Norwalk, Conn., and a button factory at Baltimore.

This move was due to the conviction of each concern that they would be better able to hold their trade in America by manufacturing the articles on the ground, and thereby saving the freight and tariff duties imposed on English goods.

It is asserted that the alcohol motor boats will be able to make the trans-Atlantic trip very easily. The saving in draft will permit them to go up shallow rivers and assist, for instance, in forcing a landing for marines; and the saving in weight. will permit the carriage of a torpedo boat by a battleship. The enactment of the free alcohol bill by Congress will cause a spurt in the manufacture of alcohol motors of all kinds, and will practically insure the success of the alcohol motor torpedo boat. The possibilities of alcohol as a fuel have so recently been discovered that one would think that the many uses to which it is being put were experimental, which, however, is not the

case.

A Safe Toy Cannon

A COLLEGE professor has, by his invention of a toy cannon, made the Fourth of July a safer, though, if possible, a noisier, day. His cannon is operated by acetylene gas, touched off by two dry batteries. The turning of a key charges the noisemaker with a mixture of air and acetylene. The cannon is fired by turning another key, and the report that follows is said to rival the thunders of heaven. As recharging by the flowing in of the gas occurs almost instantly, a skillful manipulator may fire the cannon every other second, or thirty times a minute. Absolute safety is guaranteed in its operation. The hand may be held over the cannon's mouth with impunity. The only drawback to the use of the machine is perhaps its first cost. lars is the price asked.

Five dol

Floating Steel Span THE James Bay Railroad Company of

Canada desiring to place a steel bridge span in position adopted the somewhat unusual method of floating it on scows, upon which a superstructure had been built especially for the purpose. The illustration shows the manner in which the operation was performed. Cables were attached and the strange load slowly drawn over the waters of

Lake Muskoka to its position on the railroad line. The weight of the span is one hundred and thirty-six tons.

Alaska's Telegraphs

EX

XTRAORDINARY results, in consideration of the conditions, have been achieved by the United States troops of the Department of the Columbia in the construction and maintenance of telegraph and cable lines in Alaska. The submarine cable system begins at Seattle, Washington, extends to Sitka, thence to Valdez, and on to Seward, on Resurrection Bay, a distance of 1,838 miles. Two branches, one from Sitka to Skagway, a distance of 413 miles, and the other from Valdez to Fort Liscum, a distance of four miles, make the total mileage 2,255.

The volume of business transmitted over these vables, especially the trunk portion from Seattle to Sitka, has become so great that steps have been taken to accomplish its duplexing which will make the capacity of the cable equivalent to two

wires.

The land telegraph system begins at the terminal of the submarine cable at Valdez and extends as far as Fort St. Michael. From Fort St. Michael across Norton Sound a wireless system has been installed with terminals at Fort St. Michael and Safety Harbor, 107 miles apart. From Safety Harbor a land line

[ocr errors][merged small][merged small]
[merged small][merged small][graphic][merged small][merged small][merged small]
« PreviousContinue »