Abbildungen der Seite


[merged small][merged small][merged small][merged small][merged small][merged small][merged small][ocr errors][ocr errors][merged small][ocr errors][merged small][ocr errors][merged small][merged small][merged small][merged small]


(Registered pursuant to Act of Parliament.) In the well known Pendulum Gover By reference to the engraving on nor of Watt, the centrifugal force ope our front page the construction and rates to counteract an increased speed operation of this governor will be of the machinery with which it is con easily unders'ood. It consists of an nected, by overcoming the force of upright spindle A A, near the top of gravity.

which are two equal horizontal arms, Ingenious as this contrivance un BB, furnished with stops at their extredoubtedly was, and to a certain extent milies. Two weights CC run freely to efficacious, yet it had not been employed and fro upon these arms by means of long before it was found to possess in internal anti-friction wheels. D is a herent defects, and that its action pro collar sliding upon the spindle susduced a constantly varying, rather ihan pended by two cords on chains, ff, a regular motion. The cause of this is which pass over two pullies (one seen mainly attributable to its extreme sen at g) and are attached to the weights sibility and delicacy of action, by which CC. A spiral spring, e, rests at bottom an excess of motion in either direction upon the collar D, and abuts at top continually occurs, producing a series against a sliding stop, L, which can be of variations in the speed of the en fixed at any required elevation upon gine, which scarcely ever settles down the spindle by a set screw. H is the to a regular rate of motion, unless the throtile valve lever with its forked end production of steam and the work per embracing the groove in the collar, D. formed, are of themselves constantly I is a supporting arm, and K a pulley uniform.

for receiving motion from the crank In consequence of these defects, nu shaft of the engine. merous attempts have been made to The stop L having been set so as to improve the governor; two recent pa. cause the spring to press down the tenis for this object were duly noticed collar D, with any approved force, and in our pages, and we gave at consider the throttle valve opened to the required able length in our last volume (p. 370) exient, the engine may be started. the ingenious contrivance of Mr. Hick, Should its speed exceed the stipulated in which the atmospheric resistance to rate, the increased centrifugal force rapid motion, is employed instead of will cause the two weights to recede the centrifugal force, to overcome the from the spindle, which raising the force of gravity.

collar D, will partially close the throtBy the arrangements which Mr. Hick tle-valve and diminish the supply of has adopted, gravity, although still a steam, when, the motion being checked, constant force, was capaWe of being the spring will press down the collar controlled by the quantity of opposing and withdraw the weights until the desurface brought into action, so that by sired rate of motion is obtained. varying the angle of the fans or vanes, The degree of force exerted by the a capability of adjustment was afford spring will of course always require ed, not readily attainable in the origi to be adjusted to suit the nature of the nal form of apparatus.

work thrown upon the engine, because In the governor which we have this a small quantity of steam will be reweek the pleasure of laying before our quired when the work is light, and a readers, this capability of adjustment is larger quantity when it is heavy, while still further increased, as the resistance the speed should in each case be the to centrifugal energy (which is in this same, a position which this kind of case a spring) can be increased or governor can be made to realise with diminished to any required extent. great facility and remarkable precision.

This simple and ingenious piece of In point of simplicity of construction apparatus is the invention of Mr. Henry and cheapness, as well as in the perfecDavies, the inventor and patentee of tion of its action, this governor seems to the Disc steam-engine, now attaining have a decided advantage over all considerable celebrity, and to which we

former contrivances for the same purshall probably hereafter have occasion pose, and we have no doubt will soon to call the attention of our readers. come into very extensive use.




DRY ROT-ITS CAUSES AND PREVENTION. Sir,—The phenomenon of what is who attacked my position through the called “dry rot” in timbers has been medium of the Morning Post. It turns often lamented, but almost invariably ont, however, that I was correct. There misunderstood. Certain harmless plants, is, unhappily for the cause of truth, and such as the merulius destructor, and advance of genuine knowledge, much merulius lacrymans, (so called from the favouritism in relation to the authority quantity of liquid which replenishes of a name, and party spirit runs as high the hymenium,) the latter a misnomer in the coteries of science, as in the when connected with the dry rot. These region of politics. Sir John Barrow, plants are held up to public execration in his life of Lord Anson, has entirely as the delinquents, and as chargeable impugned the efficacy of Kyan's prowith the work of destruction. They

The Duke of Portland had done stand, however, fully acquitted in the the same thing in 1838, and to the same eye of science, as the deed is already effect are the conclusions of Earl Mandone before they make their appear

Dr. Moore, in like manner, in ance, even in embryo, though their his experiments at Plymouth, had rudiments, in seeds, are already there. shown that "Kyanised wood,” as it has Like “the worm of corruption,” they been called, is no proof against the riot on decay,- it is the matrix wherein

ravages of the teredo navalis or shipthey germinate; but the disintegration worm, which was honey-combed like of the organized structure has been the rest. already consummated.

The experiments made at Welbeck It is assumed by Mr. Kyan that the in the mushroom house are very incause of dry rot is to be sought for in structive and important, and appear to the decomposition of the albumen of the be entirely conclusive. Good Baltic sap; and the chloride of mercury, by timber in these trials, lasted longer than combining with this albumen, and thus the best“Kyanised” oak. “Kyanised” forming a substance undecomposable and unkyanised oak decayed equally by the usual agencies of decay, consti fast. It appears, too, that wood impregtutes the principle of his patent. Doubt nated with Sir William Burnet's soluless albumen may be arrested in its tion, and that which was not so treated, tendency to decay by chloride of mer decayed alike. On the other hand it cury, or corrosive sublimate. It is, was proved that Scotch fir deals, and however, sheer assumption to say that copperas, (i. e. sulphate of iron,) with dry rot has to do with the albumen of lime water, resisted decay longer than the sap. Sir W. Burnet, in his counter any of them. It may be added that I patent, I believe employs a salt of zinc. had proved experimentally that sul

The great expense of mercury, the phate of copper, also chloride of copprice of which is considerably enhanced per, would coagulate albumen, and by the monopoly of Rothschild, forms therefore that this property did not exa serious obstacle to Kyan's plan, and clusively pertain to corrosive sublimate, the price of the shares of the Patent consequently that either of these might Anti Dry Rot Company shows that be substituted for it. great success does not follow their en I may, add, in this place, that Dr. terprise. Knowing that Sir H. Davy Boucherie proposes to impregnate the had selected chloride of mercury for a tree, either by the root or by the bole, similar purpose, but very properly with a solution of impure pyrolignate abandoned it from a conviction that it of iron, prior to its being cut down. would form a deleterious and destructive These two salts of iron are identical in atmosphere of mercurial vapour, I ven their operation on the sap of the tree, tured to oppose it on the same grounds, and mutually illustrate the action of contending, that in tropical climes, it each other. would be as poisonous as the quicksilver Fifteen years have elapsed since I mines of Idria, in Illyria, independent communicated to the Admiralty, through of its ready decomposition by the con Sir John Barrow the secretary, as a tact of iron and alkalis. As a matter prophylactic, or preventive of "dry rot,". of course, Mr. Kyan was quite furious, the very agent, namely sulphate of and summoned to his aid Dr. Birkbeck, iron, &c., which has thus been proved


so successful, and to triumph over all

" In the wood-cut a b c represents a others, even patent plans and projects. part of the downcast pipe, or the pipe Yours, &c.

that conveys the air from the top of the J. MURRAY. pit, or the galleries and workings of the

mine, through the bend pipe into the

upcast; b to c the bend pipe, or that ADCOCK'S PATENT SPRAY PUMP.

which unites at the bottom of the pit

the downcast with the upcast; c d e the The following extract from a communication by Mr. Adcock, which ap

upcast pipe, or pipe through which the

air, and the water commingled with it, peared in the last number of the Min

is carried to the surface or top of the ing Journal, fully illustrates the con

pit, that the water may be there again struction and action of his patent Spray collected in a solid body, and thence bc Pump, of which we inserted a descript- allowed to flow freely away; 6 6 repreive notice in a recent number.

sent five slits, through which the water “ This wood-cut is intended to repre flows from the sump or well at the botsent and explain a plan put down by tom of the pit into the upcast pipe, me at the 100-yard shaft, at Pemberton, when the apparatus is in action, that it to relieve the bend pipe and lower part may, by the current of air, be dispersed of the apparatus from any water that into drops, like drops of rain, and conmight, from accidental or other cause, veyed to the top. The downcast pipe be there collected ; and as it answers is 29inches diameter—the upcast pipe the intended purpose well, I have no 17 inches; and when not working, and doubt the wood-cit, and its descriptive from causes which it is not necessary account, will be gratifying to many of to explain, water leaks from the sump your readers.

into the apparatus, to a height equal to the head of the water there, which is about eight feet from the bottom of the bend, or 8 ft. 7 in. from the bottom of the pipe beneath the bend, consequently, the water rises to the same height in the pipe g 8 : &, which is four inches diameter; m m is a pipe, twenty feet long, that receives a supply of water from a water ring, placed so as to receive the water that oozes through and trickles down the sides of the pit. This pipe also is four inches diameter, but is unnecessarily large; it terminates in a compound cone, marked n, as shown in the figure. Of the smaller cone the dimensions may be thus stated :-Its greater diameter, 19. th of an inch; its smaller dia. meter, moth ditto; and its length 3 ditto. Of the greater cone, the dimensions may be thus stated :-Its smaller diameter, Moth of an inch; its greater diameter, 11th ditto; and its length, 54th ditto. A pipe, th of an inch diameter,

descends from the junction of the larger 7

cone with the smaller into the four-inch pipe, & 8.8&, as shown by the woodcut. This pipe is nine feet long.

“Having thus given the proportions, C18

I have only to describe the rationale of the contrivance :- The water in the pipe, m m, is maintained by the water ring, or by the water that oozes through and trickles down the sides of the pit to

« ZurückWeiter »