Sir,-The public are infinitely indebted to the pages of your Magazine, for being the first to warn the public against the dangers attending the use of Harper and Joyce's stove. If these gentlemen have erred through ignorance, the useless expense which they have incurred will perhaps be a sufficient penalty; but the party, or parties, whoever they may be, through whose instrumentality this dangerous imposition originated, deserve the most severe condemnation. A gentleman called only a few days past at the establishment for the sale of the stoves, to make inquiry respecting them, when he was informed that a person had slept in a confined apartment with one of the stoves burning all night without experiencing the slightest inconvenience; he was likewise assured, that if the prepared fuel was

used, not the slightest danger was to be apprehended! Now, this, Sir, is too bad, since it has been proved beyond contradiction, that the prepared fuel is neither more nor less than charcoal, the only difference between it and common charcoal being, that it is more perfectly charred, but possesses at the same time all the deadly properties of the former.

It has been stated, that if the stove is useless as regards dwelling-houses, it is nevertheless a valuable discovery in reference to hot-houses, &c. I imagine, Sir, that carbonic acid is destructive of vegetable as well as of animal life, and that the discovery (if discovery it can be called) is altogether a failure.

I am, Sir, yours respectfully,

12, Grafton-street, Soho, May 9, 1838.

I. S.

TAYLOR'S PATENT BOILER FEEDERSEAWARD'S PATENT STEAM-SAVER -WHITE LAW'S FEED PUMPS.

Sir,-On inspection of the Patent Boiler Feeder in No. 768, it appears to be nearly identified, the float excepted, with an apparatus patented some time since by Mr. Samuel Seaward, as a steamsaver for marine engines, having other important objects likewise in view, but which it seems has not been brought into common use, probably on account of the personal attention required by the cocks when the apparatus is in action

The plans agree so far as the close cistern placed over the boiler, and the steam and water cocks, are concerned.

Now as to the action of the feeder, I really cannot see the advantage of its employment in land engines, unless to meet some local consideration-which requires to be stated-and in such case

there will be an inevitable loss of heat from the admission of steam to the surface of the water while the boiler is supplied by the lower portion, to which the heat is slowly conducted, and whence the supply is admitted to the cistern to meet the next demand of the boiler.

What can be more simple than the long established method of regulating the supply of water in land engine boilers by the float, and valve acted on thereby? Certainly, if I understand it rightly, Taylor and Davis's patent steam boiler feeder will never supersede it, and for marine engines it is out of the question.

The inclosed sketch and description of the "steam saver" alluded to, from Mr. Seaward's specification, may be thought worth your consideration from its novelty of application, if it has not already ap peared in your most useful journal.

"I cause a vessel Z, of iron or other suitable material, and capable of withstanding. the heat of the steam contained in the boiler Y, and of resisting the pressure of the atmosphere, and of a capacity equal to onetwentieth of the water chamber of the boiler, or thereabouts; this vessel I call a receiver, and it is to be placed on the said boiler Y, as shewn in the drawing, or any where near the boiler, of a sufficient height, that any fluid contained in the said receiver, will descend by its own gravity into the steam boiler. To this vessel I attach four cocks or valves, and as many pipes, in the following order, viz.: one pipe A, from the top of the vessel Z, to the steam chamber of the

steam-boiler; one pipe B, from the bottom of the receiver Z, to the water chamber of boiler; one pipe C, from the bottom of the said receiver to the water outside the ship; and one pipe D, from the top of the said receiver, to the well or lowest part of the ship in which the boiler is placed.

"The first operation of this apparatus for the effecting the saving of fuel is as follows: -When the steam is so high as to raise the safety-valves, and escape, either in consequence of the engines standing still, or the too great quantity of fire, the cock A is to be opened, and the receiver Z filled with steam, the air rushing out by a small cock E, placed at the top. The receiver being

full, the cock A is to be shut, and also the cock E, and the cock C opened; the steam contained in the said receiver will by this operation be condensed, and a partial vacuum thereby be formed; the water will then rush from outside the ship, and fill the receiver; the cock C being then shut, and the cock B opened, the water will descend slowly by its own gravity into the water chamber of the boilers; and this can be accelerated by again opening the cock A, by which means the water will descend at a heat not much below that of boiling water. The saving of fuel will be evident, because, at all times, the boiler may be completely filled, and the water itself raised to a high temperature by the steam, which would otherwise escape at the safety valves, and be completely lost.

"The second operation is that of pumping or drawing the water from the hold of the ship. To effect this the cock A is again opened, and the receiver thereby filled with steam; upon closing the cock A, the cock D is opened, and the water will rush up from the hold of the ship, and fill the receiver; the cock D being shut, and the cock C opened, the water contained in the receiver will run overboard, by opening the small air cock E in the top. This operation can be repeated till the ship is perfectly dry fifty or sixty tons of water per hour can be discharged with great facility in a boat of 100 horses' power, by simply employing the spare steam while the engines are at rest."

66

Since writing the above, I received No. 769, with a frontispiece and description of another feeding apparatus, to be worked by a separate steam-engine! with chests," "casings," "slide valves," and other details, which are left out to avoid complexity! (vide sketch) which certainly displays much ingenuity, and is intended as an illustration of their application to marine engines. It would appear that Messrs. Taylor, Davis, and Whitelaw have taken a great deal of pains, the latter gentleman especially, in contriving to meet a defect in the steam-engine which exists but in imagination.

I have already remarked on the simplicity of the existing apparatus in ordinary land engines, with the feed head or equilibrium pipe; and where steam of high pressure is used, the feed-pump forces the water directly into the boiler, regulated by a stop-cock and loaded valve, through which the surplus is conveyed to waste; and in many places a cock is fitted to the suction pipe of the pump, so as to regulate the supply by admission of a portion of air, and thus dispensing with

the loaded valve, which passing into the boiler with the feed, is no doubt objectionable in condensing engines.

In many cases the height of water within the boilers is regulated by a float acting on the stop-cock before mentioned.

Now in marine engines, from the constant fluctuation of the height of water in the boilers, both from the influence of the sea, and from the necessity of accumulating water for blowing off, and diminishing the same in performing the latter operation, experience has shown that the ordinary feed pump, with its stop-cock and loaded value, is the most simple and efficient contrivance: all schemes for regulating the feed by floats, &c., having been abandoned long since as unsafe from their liability to throw the engineer off his guard, who might place too much confidence in their doubtful performance.

It appears moreover that the precision of Mr. Whitelaw's feeder mainly depends on the compression of a certain bulk of steam, admitted at each stroke of his slide valve-compression of steam (that is, increasing its elastic force) by injection of a charge of comparatively cold water! Surely Mr. W. must have lost sight of the fact, that his feed will be cold in the case of a high pressure boiler, or nearly so, and will not be above 100° if discharged from the condenser of a low pressure engine; so that on the outset his principles are mistaken, without reference to the absurdity of employing a supplementary engine, with its additional cost and expense of maintaining.

Now Taylor and Davis's plan would effect that which Whitelaw's engine is expected to do, under all circumstances, with the advantage of greater simplicity at least, to recommend it. I am, Sir,

Your most obedient servant,
NAUTICUS.

Woolwich, May 7, 1838.

P

the appearance of those interesting particulars which Mr. B. (when he announced his discovery, eighteen months ago), led them to suppose would be published in its pages?

I cannot but express surprise at the very nonchalant way in which Mr. Baddeley speaks of his plan, even in the same paragraph which states his continued confidence in its perfect practicability. One would imagine that few more pressing engagements" would be allowed to stand in the way of introducing to the world an invention which would instantly take its place as one of

the most important of modern times,
and infallibly immortalize the name of
its discoverer into the bargain! At any
rate, if only to silence the incredulous
many, who may be apt, on this occasion
as on others, to insinuate that what
seemed perfect in theory has failed in
practice, it would surely be worth Mr.
Baddeley's while to make public the de-
tails of his scheme at once.
I remain, Sir,

Your obedient servant,
PHILO-BADDELEY,

London, May 2, 1838.

A B C represent an instrument similar to a pair of compasses, the legs of which are moveable on the joint C; the leg B C is somewhat longer than A C; the latter is a cylindrical piece of hard steel wire pointed at the end; t is a hollow tube which slides up and down the leg A C; to this tube is attached the piece DE P, having two joints to allow the pencil P to be placed in a position parallel to the leg A C; there should be a milled-headed screw at each of the two joints D and E to make them tight when adjusted to any given position.

T

B

To describe an ellipsis, place the point A on the centre of the ellipsis, the point B must be placed on the continuation of the longer diameter, then open the point

P till the pencil coincides with the end of the shorter diameter, turn the tube a quarter round, and if the pencil should not coincide with the end of the longer