The Mechanics' Magazine, Museum, Register, Journal, and Gazette

of wind and rain. A powerful light to a, is the 'furnace; bb, reverberating distinguish the admiral's ship is a matter draughts; cc, retort; aaa, section of a of the utmost iinportance during war, or cone formed of sheet-iron; ee, dry lime when a storm has dispersed a fleet. purifiers; f, gas-pipe; g, a hydraulic or A gas-light of sufficient size placed at sand-joint; h, a cast-iron cover; i, chim- the bows of the steamers employed on ney. The coals from which the gas is the Thames, would render the navigato be extracted are placed in the retort. tion of the crowded parts of the river The distillation is effected by the action much easier and safer, as it is well known of the hot-air produced by the ignited that the majority of accidents which coke in the furnace; this hot air, by have happened of late years on the river, traversing the passages shown by the are to be attributed to the defective conarrows in the centre cone, distributes a dition of the bow-lights. This apparatus uniform heat to every part of the retort.

will also be useful in cases of shipwreck The gas, as it evolves, passes through in saving the lives of individuals. the purifiers e e, and deposits all its im. Air and water-tight vessels constructed purities in the layers of lime spread upon

of caoutchouc and inflated with gas, will, the shelves.

by judiciously attaching them to the gunIt is likely to strike any one upon a wale of a boat, effectually prevent her first view of this machine, that a consi- from swamping, and enable her to ride derable addition to the usual cargo of through the most tempestuous sea. coals would be necessary to its working The apparatus occupies about three on board ship; but the contrary is the feet six inches square, and six feet in case, as the same stock of coals, after height. having supplied gas for cooking and To guard, hospital, convict, or prison lighting, and diffused warmth through ships, this machine will be exceedingly the vessel, will actually yield one-fourth beneficial, both in respect to economy more than its original quantity of coke: and comfort. hence, there is a decided increase of fuel Light-louses may also by the same aster having obtained from the coals the process be illuminated at half the prealready enumerated advantages.

sent cost. To this latter application of The saving which will result from his contrivance, and to a method of caradopting this contrivance in the Royal rying on telegraphic communications Navy and Merchant Service will be during night, Mr. Hutchison has de considerable, especially with respect to voted much of his time; his attention is at oil, candles, fire, wood, and coals.

present engaged upon the subject; and The gas-generator appears to be pecu- after he has inatūred bis plans and calliarly adapted to those vessels that trade culations, the results of his investiga to India and the Tropics, as it sis well tions are to be laid before the public. known that passengers (particularly in

C. valids) are subjected to great incon- London, March 11, 1836. venience from alterations of temperature, which are frequent during such voyages. Those evils may now be, in a great mea

CORNWALL POLYTECHNIC SOCIETY. sure, remedied, by regulating (through We have before spoken of this Society the supply-valve) the exact degree of in terms of high praise; and judging warmth deemed necessary for the health from the third Annual Report, which it and comfort of the passengers; and, by has just issued, it has worked hard to the same means, the gas in the galley, make good its title to the rank we as

CORNWALL POLYTECHNIC SOCIETY.

signed to it of being one of the best, “The performance of two atmospheric en if not the very best of the institutions of gines, at Poldice, had been ascertained as a its class. Agreeing, as we do, in a great standard of comparison, and declared by a measure with our correspondent P.P.C.R.

Committee: for convenience the present (No. 660,) that the number of permanent

dynamic unit was afterwards adopted, and

the work done when thus expressed was equal Scientific Institutions and Museums is

to 7,037,800 lbs. lifted one foot high by each very small, we are the more delighted to

bushel of coa A dispute arose in 1798 observe the strong indications of lasting

between Messrs. Boulton and Watt and the prosperity and usefulness evinced by our

mining adventurers in Cornwall, and it beCornish favourite. Patronised by the

came necessary to ascertain the average duty, King, and having upon its roll of officers which was proved to be 17,671,000 lbs. : this some of the first scientific names in the was rather less than in 1793, when the avercountry, and others of the highest local age of seventeen engines was 19,569,000 lbs. influence, science cannot but continue to After the expiration of the patent in 1800, flourish under its protecting and fostering

no accounts were kept of the work performed care ; and more especially, while its ma

by the engines under the direction of the nagers continue to follow out the sensible

mining engineers. plan of operations avowed in their present

“In August, 1812, the average duty of report.

several engines on a month's trial proved to

be only 134 millions, and the truth of the “The principal cause to which your Committee would attribute the success of their

prevailing opinion became apparent that less

work was done than during Watt's patent. past proceedings, and the quarter to which they would chiefly turn for hopeful encourage

The present monthly report of work per

formed' was then established under the ment in the prospect of the future, is the

management of Mr. Lean, and since his adaptation of the society to the tastes, habits, decease has been conducted by his son, so employments, and capabilities of the country. that there exists a series of reports for twentyBut for this, they durst not anticipate any thing beyond a brief and ephemeral popu

two years, showing the duty for each month

of the large engines employed in Cornwall, larity. No sustained and permanent result

including the size of the pumps, and their should be hoped for from any mere adventitious stimulas."

depths, number of strokes, bushels of coal

consumed, &c. &c.; a reference to which Cornwall, as all the world knows, was would point out at what period, and by whom, the nursery of the steam-engine. The every increase of duty was obtained. vast quantity of water which had to be « Woolf introduced the use of high-presraised from its many valuable mines, in sure steam worked expansively in two cylinorder to keep them in a workable state, ders, and first succeeded in performing fifty prompted and rewarded the exertions of millions. Other engineers worked high Savary, Newcomen, and Watt; and this steam expansively in one cylinder, which district still claims a great superiority in

plan became general on the introduction of its engines over every other. The re

Trevithick's cylindrical boilers. ported results have, it is true, been re

“ Several engines now constantly perform ceived with incredulity in some quarters;

à duty exceeding 70 millions, double that of and the alleged superiority has been

the best of Watt's, and of which one has stoutly questioned, if not absolutely de

reached 91,200,000; another mentioned last nied. We have, for our own parts, how

meeting by our President, averages about ever, no doubt whatever on the subject, 97,800,000, for one month.

90,000,000 ; its best performance and look upon the facts stated in the fol. lowing brief hisiorical summary, by Mr.

“ Part of the increase of duty must be at

tributed to the improved pitwork; the most Enys, as not only indisputably established,

rapid increase, however, took place on the but quite scientifically accounted for :- introduction of a most complete system of

“The mode of estimating the performances clothing, the present practice of which is so of steam-engines, by the number of lbs. lifted efficient, that in two instances, though the one foot high by the consumption of a bushel af steam in the jacket was at least 270°, the coal, was introduced into Cornwall by Watt, outside casing did not exceed 78° ;--the therwhen it became requisite to keep a regular mometer was covered by a silk handkerchief account of the work done and coal consumed, to prevent the draught of air in the enginefor the purpose of calculating his share, house affecting the results ;-the air outside which was one-third of the saving of coal was in one experiment 56°, and in the engineeffected by his engine in comparison with house, about 66°;—the surface of the ashes Newcomen's.

over the boilers was about 900.

was

« iepriekšējā Turpināt »

Grāmatas

The Mechanics' Magazine, Museum, Register, Journal, and Gazette, 25. sējums