have brought it forward as an argument against my plan, for it applies only to one modification of it: the modification given in the P.S. to my letter has not this defect (granting it to be one).

If the modification of my plan of feeding boilers, given in the P.S. to my former letter, be adopted, it will be an improvement on it to send the feed water in at the top, and not at the bottom end of the chest k; for then the steam in the chest will heat the water pumped into it. As Nauticus admits that my plan is “ingenious," it certainly would have been more to his credit if he had tried to improve it in the way here shewn, or in any other way, than to condemn the whole on account of one or two supposed faults in some of its forms. In the modification of my plan described in this paragraph, no cold water will pass into the chest k after it is filled, and displace the hot water in it, if the loaded valve and the pipe into which it is placed have a position to counteract the circulation, which is sometimes caused by hot and cold particles of water being in different parts of the same set of pipes or vessels.

"Nauticus" is certainly not in earnest when he says that he considers Taylor's plan preferable to mine ; for surely, valves wrought by an eccentric will have a more certain action, than stop-cocks wrought by means of a float can have.*

I must object to the appending notes of exclamation (!) to remarks upon contributions by correspondents-a sneer is implied by them, which is not deserved by anyone who wishes to benefit your readers by publishing a useful or novel idea. I am, Sir, yours respectfully, JAMES WHITELAW.

IMPROVEMENTS IN GAS-STOVES, ETC.

Sir,-Since the " new heating apparatus" has been at such a woeful discount, gas-stoves have again been “ looking up," and appear likely to recover from the damper put upon them by the exaggerated announcements of the Jerusalem conjurors. I think there is little

The following errors of the press appear in my last communication:-In page 67, line 3, from the top, for "pipe g," read "pipe q;" the same error is repeated in page 68, line 15 from the top. In page 7, line 19, from the bottom, "" should read "u"; nd in the same page, line 13, from the bottom, bottom" should read "top."

doubt that before cold weather (properly so called) revisits this hemisphere, ingenuity will have devised such improvements in the management of gaseous fuel, as to render it a desirable, and in many situations an indispensable mode of house-warming.

Having worked one of Rickett's patent gas-stoves through the late severe winter, I can bear testimony to the efficiency of this apparatus; at the same time I must admit, that there is plenty of room for actual improvement. There is, however, so much ignorance prevailing, on the subject of heating generally, and the properties of carburetted hydrogen gas, as a source of light and heat, are so imperfectly understood by a majority of the public, that the march of real improvement in these departments, is any thing but rapid.

A plan for an improved gas-stove appeared at page 82, of your present volume, which is in reality a poor attempt at improvement. It is a very common error with many persons, to imagine, that atmospheric air which has been deteriorated by contact with hot metallic surfaces, may be restored to its pristine purity, by admixture with the vapour of water; it is therefore recommended to place a vessel of water upon, or within, the heating apparatus for this purpose. Whatever benefits may arise from the admixture of vapour with the arid atmosphere of an ordinary hot-air stove, its application to gas-stoves is highly absurd. On reference to the very interesting exposition of the phenomena of gas-stoves published at page 391 of your 26th volume, it will be found stated that, a stove which burns 15 cubic feet of carburetted hydrogen gas per hour, forms 39 cubic inches of water (nearly a pint and a quarter) and 15 cubic feet of carbonic acid gas. There is no difficulty, then, in accounting for the fact, that the windows where such a stove is used are covered with mois ture;" for if the stove be used for fourteen hours a day, it will in that time form just two gallons of water, which must all be deposited on the windows and walls of the room, or on any other cold surfaces. There are no means of preventing this formation of water, as it has no connexion whatever with the nature of the materials of the stove; for, whenever hydrogen gas is burned with oxygen, water is necessarily formed."

The demonstration of this fact is a continual source of annoyance to shopkeepers and others, whose bright steel and iron goods soon shew very plainly what is going on; besides, the windows being so dimmed by the moist deposit, as to render the goods exhibited therein, "invisible or dimly seen." A mechanic of great celebrity lately employed a gasstove for warming one of his workshops, but was soon compelled to abandon it; his valuable and delicate machinery becoming covered with rust. The evil was attributed to the escape of unconsumed gas, but this was a mistake; the mischief arose from the water resulting from the combustion of the two gases. A slight glance at these facts will be sufficient to shew the absurdity of any scheme by which increase of humidity is sought to be obtained. Our friend Col. Macerone seems to have blundered in this matter; at page 369, volume 26, he alludes to the aqueous moisture generated by gas-stoves, and endeavours to explain the phenomenon, by his electrical theory of the universe. "I suppose," says Col. M., “such gas to consist of an electric or galvanic globule, inclosed in a vesicle of water. This water is set free upon the combustion of the gas, and may account for the deposit referred to." And yet, in the face of this statement, at page 298 of your last volume, we find him advising the application of a cup of water to a gasstove to give the necessary humidity to the respiring medium!

Of all the gas-stoves I have yet seen, Rickett's is by far the best; indeed I have seen some so truly barbarous, that I should be ashamed to mention the maker's name. There is one in my own neighbourhood, made of sheet-iron, very badly put together, and constructed in direct opposition to the principles upon which the due performance of this stove entirely depends; the quantity of gas expended in producing a very small degree of heat is enormous. A supply of gas cannot be obtained in the day-time, or the expence of this stove would be ruinous. Should gas become generally employed for the purposes of heating, the supply must be continued throughout the twenty-four hours, which will perhaps lead to a universal system of supplying by meter-a system which I am well convinced would be highly advantageous to both buyer and seller. If the several gas companies knew their own

interest, they would not supply their commodity, except in known quantities, at a definite price; and were consumers equally enlightened, they would receive it on no other terms. Such persons as chose to be prodigal in their lights, &c. would pay accordingly; while those who chose to economise their consumption, would receive the full benefit of their frugality and care. Under such arrangement, less gas would be wasted; defective fittings would at once be restored, and the number of serious accidents from the escape of gas, would be greatly reduced.

Several of your correspondents have recommended the use of sheet-iron in the formation of gas-stoves, in preference to casting in choosing between the two materials, there is much to be said both pro and con.; different advantages and defects being peculiar to both. The cast-iron stoves being a larger mass of metal, cause the temperature to be more evenly preserved; and without any portion of the metal being made so hot as to decompose the air of the apartment. Mr. Ricketts is now introducing diluted gasstoves, for domestic and manufacturing purposes, which offer many advantages over the original method. When carburetted hydrogen gas is mixed or diluted with atmospheric air, the combustion is more perfect, and the heat more intense, than when pure gas is burned. For the first practical application of this fact, we are indebted to Sir John Robison, the talented and much-respected secretary of the Royal Society of Edinburgh, who employed diluted gas-stoves, and pointed out their great superiority several years back. The flame of diluted coalgas is the very best heat that can be employed for hardening of small steel articles, as it does not black or scale the surface. From the great attention that has been paid to the subject of coal-gas in Scotland, the Scotch are far before us in a correct knowledge of its use and properties; as also in its useful applica tion to many of the ordinary concerns of life.

Of all the methods for diffusing artificial warmth within our dwellings, the radiation of heat from vessels filled with water, is by far the best. In this case the apparatus can never become so hot as to injure the wholesome character of the atmosphere; while, at the same time, the free circulation of the fluid particles

ham.

The improvement consists in placing the rotator V within a strong iron frame, which will effectually prevent any injury happening to it when the lead O strikes the ground, which might occur on a rocky bottom. The lead O, which sinks the machine, is attached to the frame-work containing the rotator and index plate C, by a piece of rope N. At the bottom of the lead is a receptacle for tallow, by which the nature of the bottom is ascertained. This machine will give correct soundings when going 9 or 10 knots through the water, without heaving-to, or deadening the ship's way, by giving it plenty of line, as it only registers the perpendicular descent, and has no connexion whatever with the quantity of line in the water. There is a flirt piece, or lock, at the back of the indexes, which is not shown in the engraving, which is kept in an upright position during the descent of the machine by the action of the water, but which immediately falls when the lead strikes the bottom; or also when the machine is hauled inboard, should the vessel not be in soundings, which prevents the rotator acting while being hauled in, which would cause an error in the soundings. I have only to add, that I have repeatedly got correct soundings at a depth of from 25 to 30 fathoms, from on board a steamvessel at full speed, which speaks volumes for the utility and value of the machine.

I remain, Sir, your obedient servant,
AN OLD SAILOR.

Dover Road, May 22, 1838.

invented by Messrs. Massey and Wind

MR. UTTING'S ASTRONOMICAL TABLES

-A SCOTCH DOMINIE IN REPLY.

Sir, I return Kinclaven my best thanks for the assistance he has given me in his letter in No. 764; at the same time, I beg leave to inform him, that it was my intention to have replied to Mr. Utting's last letter in No. 754. Indeed I had nearly finished a reply to it, when I received the number containing Kinclaven's letter, and found that he (Kinclaven) had anticipated me in several remarks which I intended to have made; under these circumstances I thought the better way would be, to write a new one, and to go a little more into detail on some of those parts of Mr. Utting's letter which Kinclaven has only glanced at; and this I very much regret, as I am well

aware that he is far better qualified for the task than I can pretend to be.

In the first place, Mr. Utting informs us in his letter above referred to, "that the motion of the equinoxial points varies in proportion to the periodical times of the planets. This is surely a most important astronomical discovery if it should be found to be true. Well we shall see : -assume 50.1 as the precession of the equinoxial points of the earth, to determine those of Jupiter; then by Mr. Utting's simple rule we have 365.25 + &c.: 50".1: 4332.60+&c. : 591".55; that is, the precession of the equinoxial points of Jupiter in one periodical revolution of that planet is 591".55 or 9'.. 51".55.

TT T-T there is not an equality between the expressions.

; but even in the case of Jupiter

We shall now proceed to enquire how affairs go on with some of the other planets, according to Mr. Utting's general rule. And first we shall take the planet Mercury, the periodical period of which is 87.969150; hence, according to the golden rule of Mr. Utting, 365.254, &c. 50'.1 87.969 + &c. : 12′′;07.Solution by the true rule:-The tropical period of Mercury is 87.968434; .000716 and a 10".44; that is,

:

:

1296000 X .000716 87.969+ &c.

==

=

the error produced by Mr. Utting's rule in a periodical revolution of Mercury is 1".63; or the error for a periodical revolution of the earth will be 6′′.8. Proceeding in the same way with the planet Venus, Mr. Utting's error will be found to be no less than 19".1 in one siderial year. But surely, Mr. Editor, you, as well as your numerous scientific contributors and readers, will allow that I have advanced quite enough to show the absurdities that result from Mr. Utting's newly-discovered rule. No doubt from some of those long arithmetical calculations of which he is so fond, Mr. U. discovered that his rule was nearly true with respect to the Earth and Jupiter, and hence he very unscientifically concluded that it must universally hold good.

I was very much amused (edified I cannot say) with Mr. Utting's two solutions of the question I proposed him, and inserted in No. 747 of your Magazine, the first of which he has taken from the Philosophical Magazine. The synodic period being found to be 399.976169 siderial days, or 398.884105 (according to Kinclaven) mean solar days. Mr. Utting, from his manufacturing system, has calculated the said period to be only