certain point. Her steering qualities are also first-rate. She may be left ten minutes or more, when under canvas, and hold a perfectly straight course, without the necessity of touching the rudder.

[The Water Lily is a smaller vessel, and of less engine power, than either the Fairy or Meteor.

Her length is 132 ft.; breadth,

16 ft. 6 in.; cylinders, 29 in.; stroke, 14 in. Seeing that she went the distance from Blackwall to Portsmouth in 17 h. 11 min., this is a greater performance than that of the Fairy, which took 17 h. 56 min. to perform the distance from Greenhithe (only) to the same port of destination.—ED. M. M.]

REMARKABLE EFFECT OF THE LATE
THUNDER STORM.

Sir,-If the following phenomenon is new, or likely to be of interest to your readers, you will please insert it in your next Number. On Sunday evening the 6th inst., the neighbourhood of Birmingham was visited with an awful thunder storm, which lasted about one hour and a quarter; the lightning was nearly constant flash after flash, with a heavy fall of rain, such as I never saw before. Next morning I visited a copperas manufactory (sulphate of iron), and to my surprise I found the whole surface of the copperas liquor which was in the crystallizing vessels completely of a bloodred colour. In the course of to-day a red powder began to separate from the liquor and fall to the bottom, so that by six o'clock in the evening the liquor had nearly resumed its original colour. It appears to me that the sulphate of iron had been decomposed by the lightning, and a peroxide of iron formed. presume the sulphuric acid has been converted into sulphurous acid, and escaped. Probably this fact may throw some light on the application of electricity to agricultural purposes. There is no doubt but the electric fluid has the power of decomposing the salts of iron, and converting the iron into a peroxide, which we know absorbs ammonia rapidly. May not the peroxide, then, have the effect of retaining the ammonia until the vegetable takes it up by its roots for assimilation, and so act as a carrier of ammonia from the atmosphere to the vegetable? And may not all the alkaline, earthy, and metallic salts be decomposed in a similar manner in the earth, and not by vegetable life?

I am, Sir, your obedient servant,

July 7, 1845.

R. W.

NOTES AND NOTICES.

Telegraph over the Atlantic!-A writer in the New York Tribune suggests a plan for bringing Old England within a speaking distance. He proposes to run a copper wire, well covered, and as large as a pipe stem, from Nova Scotia to the coast of Ireland. This, as is thought, may be accomplished by winding the wire upon reels, and arranging it on board a steamer so as to be reeled off as fast as the boat goes, and dropped the whole width of the Atlantic. The writer says-" Its gravity would sink it to the depth where water was so dense as to be of equal gravity, and of course beyond the reach of any kind of collision. Beginning and ending upon a bold shore, beyond the reach of anchors, it would be out of harm's way, and exposed but to two kinds of accidents, viz., from separation by its own weight, and the loss of the coating with which the metal must be protected. The steamer Great Britain would carry more wire of this size than would extend to Europe, and its cost, I think, would be less than a million of dollars."

A Giant Stride in Photography.-A M. Martenz, of Paris, states that he has discovered the means of carrying on the Daguerréotype process on a gigantic scale. He can, he says, Daguerréotype an entire panorama, embracing 150 degrees!! His process consists in curving the metallic plate, and causing the lens which reflects the landscape to turn by clockwork. The lens, in turning, passes over on one side the whole space to be Daguerréotyped, and on the other side moves the refracted luminous cone to the plate, to which the objects are successively conveyed.

We

Patent Burrel Cleaning and Drying Process. -We some time since gave a description of the process for cleaning barrels, patented by Messrs. Davidson and Symington, which we had seen in operation at Messrs. Hanbury's brewery. understand, that not only has this process been in constant operation, with the most beneficial results, in that immense establishment, and in many others in which it has been introduced, but that the method of producing a continuous stream of hot air, which forms part of the barrel-cleaning process, has been applied with great success and economy to starch-making, coffee-roasting, calico-printing, and other matters in which a high controllable temperature is required. We think it right to return to the subject of this important patent, because a paragraph from the Birmingham Advertiser has gone the round of the papers, assigning the embarrassment of Messrs. Alsopp, the Pale Ale brewers of Burton, to "the failure of a patent process which they had purchased." Now we are enabled to state, on the best authority, that Messrs. Alsopp's difficulties have no relation whatever with any patent, but have arisen mainly from want of sufficient capital to support their large export trade. A want, we sincerely trust, which will shortly be supplied. It is true that Messrs. Alsopps have made use of the process, but, as they themselves acknowledge, not in the manner prescribed by the patentee; while Messrs. Bass, their neighbours and rivals, have used, and are still using it, with the most complete success. Patentees have so much to contend against, and patentees of mechanical improvements such enormous expenses to incur, that they deserve all the assistance the press can afford them.-Great Western Advertiser.

INTENDING PATENTEES may be supplied gratis with Instructions, by application (post paid) to Messrs. Robertson and Co., 166, Fleet-street, by whom is kept the only COMPLETE REGISTRY OF PATENTS.

The present improvements, though they resolve themselves into what may seem at first sight but a small matter, are in truth of great importance. The spinning of flax, in overcoming the intractability of which, so much mechanical ingenuity has been already expended, is not only greatly facilitated by them, but thread of a much superior quality produced. The improvements consist simply in passing the slivers of flax through water, or through some colouring fluid substance, while they are yet in an untwisted state, and in the additions to, and modifications in, the ordinary spinning machinery required for the purpose.

Fig. 1 is an end elevation of a flaxspinning frame, adapted to, and embodying Messrs. Russell and Peter's improvements; and fig. 2, a sectional view of the parts to which their invention has more especial reference, detached from the rest.

A, fig. 2, is one of the retaining rollers; B, one of the drawing rollers; C is a trough, which is filled with water, or with some fluid colouring substance. S S represents the sliver of untwisted flax which, after it comes from between the drawing rollers B, is carried under a small roller, D, which is partly immersed in the water, or colouring fluid, and

thence carried upwards, over and between two compressing rollers, E F, which keep the sliver still untwisted, and serve also to free it from any superfluous moisture which it may have taken up. The sliver, after being thus wetted or dyed in an untwisted state, is passed to the other parts of the machine, to be spun in the usual way.

Other fibrous substances, as well as flax, may be prepared for roving and spinning in the same way, with more or less advantage; and the patentees include in their claim a title to any such extension of their invention.

THE

DAGUERREOTYPE PROCESS - THE LENSES PROPER FOR THE PURPOSE.

Sir,-In reference to Mr. Cumberland's suggested improvement in the Daguerreotype process, vol. xlii. p. 421, I beg to observe, that metal specula for taking daguerreotype portraits have been in use for three or four years, or more; but at the same time, I believe it would not be difficult to show that cameras constructed with a speculum were before known. The great expense and impossibility of making them accurate has, however, hitherto precluded their general use. One of Mr. Beard's patents in

cludes the speculum camera.

"The

Mr. Cumberland observes: mode at present practised is by refraction of the sun's rays through a convex lens, which, unless composed, as I have sometimes constructed them, of two planoconvex lenses, is always subject to limited aberrations, and, indeed, in all cases, gives a distorted image to a certain degree, although not always perceptible to the eye." This conveys the idea that Mr. Cumberland has, by combining two plano-convex lenses, succeeded in doing away with the aberration that has always been known to attend the images given by lenses of any, and every form. It would be a pity for any one to be led astray by such remarks to waste his time and money in fruitless experiments to accomplish an impossibility-viz., to cause any convex lens or any combination of lenses, however shaped, to make a clear, sharp, distinct image. No lenses or combination of lenses can do this, unless made of different refracting substancesnone but achromatic lenses will do it. All those daguerreotypes made by specula

35

But

that I have seen have not the sharpness peculiar to those made by achromatic lenses. We all speak by comparison. Mr. Cumberland may have found that his arrangement of lenses was the best he had tried. Mr. Hunt considers that a periscopic lens is the best. I have tried almost all the lenses and likely combinations in Sir David Brewster's volume on Optics (Lardner's Cyclopedia), and I simply beg to state the fact, that neither such lenses as have hitherto been known, nor any combination of them, have ever given or ever can, give a sharp image (except those called achromatic). an achromatic lens 3 inches diameter, and 15 inches focus, will not give an image clear and distinct enough for daguerreotype purposes; part of it must be stopped out so as to leave an aperture of only 1 inch diameter; if the aperture is made 1 inch diameter, the image will be so sharp, that any further diminution of the aperture does not perceptibly improve the sharpness of the image. Any one who has used an achromatic lens and seen the clear image produced by it, cannot afterwards call the images produced by other lenses sharp. If it was possible to form a correctshaped parabolic lens, it would give a perfect image.

I am, &c.

Carmarthen, July 10, 1845.

Номо.

P. S. Will any of your readers be kind enough to furnish a description of "Storer's Delineator"?

BAROMETRIC PRESSURE AT THE ANTARCTIC CIRCLE.

Sir, The discovery of Sir James Ross, mentioned in your periodical of the 5th instant, "that a permanently low barometric pressure prevails over the whole of the antarctic ocean," however difficult to explain by modern modes of philosophising, presents no difficulty on principles truly natural.

The principles are these: Matter is inert; so must all bodies be inert; inertia implies want of ability to perform any kind of act to produce any kind of effect. Motion is not natural to anything material, moving being acting. There can be no

*For reasons, see any elementary work on Optics.