clear it was a compound cement, and not the cement for the application of which our patent was taken out. The exhibition of the balloon, though it were to thousands, was not a publication of its construction; the spectators could not tell whether it was of one fold or two, or how the seams were united. The publication depends, therefore, upon what is said by his son, and what is said by the attorney, in contradiction to that which Green himself has solemnly sworn. The last witness on this point knew nothing about the matter; he went up, he had a shred of the wreck of the coronation-balloon, but he never heard how it was made. The passage in Baron Humboldt's book proves nothing, even supposing his fabrics had been united by the pure milk of the hevea. My friend may just as well say that barley is the same as beer or as alcohol, and milk as toasted cheese, as that the milk taken from the hevea is the same as the dissolved caoutchouc. The observations which I have made with regard to Humboldt apply to the Doctor from Demerara, and show that that process is entirely different. These were merely experiments, which had failed on account of this caseous substance, which was of so of fensive a smell that they could not be used, and they had altogether been discontinued. I have now to draw your attention to Johnson's patent. The part of his specification in question is this." As to the waterproof compound I proceed as follows:-After the linen, woollen, cotton, or silk stuffs, or cloths, hats, or leather, are prepared by the above-described blanching lixivium, I stretch them into a frame, and having dissolved caoutchouc or India-rubber in spirits of turpentine (the smell of which is taken off by oil of wormwood) and spirits of wine, in equal quantities, the caoutchouc (having become a varnish) I spread with a large piece of the undissolved caoutchouc (instead of a sponge or brush) upon the wrong side of the prepared stuff, or cloth, or leather, and then sift over it." He does not put another piece, but "sift over it any coloured cloth, or silk, or worsted, or cony, or other wool, cut fine in the same manner as flock-paper is made, and being left to dry for a day or two by the flock, by its adhesion to the caoutchouc, is equal to any lining." This, gentlemen, is a patent, I believe, like the great majority, that fall stillborn, are never brought into operationthere is no proof that one single specimen ever was made from 1797 down to 1836; and whether it was for a flock-paper or cloth for garments, there is no pretence for saying that it is at all of the same nature as the process described by Mr. Macintosh. Mr. Hancock's patent, dated in 1825, is brought forward, but no subsequent discovery, no

subsequent use, no subsequent process, no subsequent application of any thing that may have since been discovered, can in the slightest degree affect the validity of Mr. Macintosh's patent; and although it is there mentioned that the coal-oil should be rectified, it is not necessary that it should be highly rectified for many purposes, and so to have introduced these words would have rendered the patent void. My friend has tried to throw some ridicule on the Chemical Club. Gentlemen, I should have thought the memory of Dr. Wollaston might have been treated with more respect; he was a distinguished member of that club, which was a focus of information, to which every discovery made in the most distant parts of the empire was soon conveyed, its merits tested, and a judgment pronounced. All the members who have been examined say, if there had been such a process known they must have been acquainted with it, and they hailed it as a discovery of the greatest importance. If you decide that the patent is good, the infringement has been proved,one of the defendant's cloaks, put forth as Faushaw's patent, has been bought by a witness, and pieces of it analysed by chemists, (Messrs. Phillips and Garden), who say that they have no doubt but that it is the same as Macintosh's.

The Lord Chief Justice then proceeded to sum up, but was in a short time stopped by the Jury, who returned a verdict for the plaintiffs.

BRITISH MUSEUM.

Sir, I beg to call the attention of your readers to a petition about to be presented to Parliament, praying for a reform in the management of the British Museum; the opening of the establishment in the Easter, Whitsun, and Christmas weeks, and during certain hours on Sundays; and for the erecting of a detached fire-proof reading-room for evening visitors. Of the necessity for these alterations and improvements there can be no question; and if the petition were signed, as I think it will be, by a very considerable number of persons, its highly valuable objects would be obtained.

I am, Sir,

Yours, &c.

F. S. A.

IMPROVED THROSTLE FRAME-SPINDLE.

a

Sir,-The above figure shows a throstle frame-spindle of a different construction from those in ordinary use. The principal advantages which this form of spindle has over the other forms are, first, less tendency to vibrate, on account of the collar which supports its top end being placed quite close to the flyer; it is also much lighter, and for this reason it may be driven at a very great speed; and as the spindle has no vibratory motion, the strain on the thread, occasioned by the

friction of the bobbin, is very uniform. The only disadvantage in this plan is, that when the thread breaks, it is rather difficult to piece, as the thread has to be pulled through the hole in the tube or stud which supports the bobbin, by means of a wire hook; but this, I think, is more than compensated for by the draw of the bobbin being so very uniform, that the thread seldom breaks, unless a part of it happens to be bad, and in this case it should be broken.

I have had a spindle on this principle working for a considerable time now, making thread, and it answers its pur. pose well. The quantity of draw of the bobbin may be altered at any time, by placing a cloth washer, of the proper size, on the top of the flanch of the tube If more which supports the bobbin.

draw is wanted for any purpose, than can be easily obtained in this way, a groove may be turned in the top flanch of the bobbin, so as to receive a string, which is pressed against the bobbin by means of a small weight.

I cannot show the method of slipping —that is, the way in which the bobbins are taken off and put on to the machine, without another sketch. I have a very speedy method of doing this, and will give it, as also the way of carrying the twist up to the rollers, if the machine is used for spinning, should the invention be fully proved, if it is found to be a good one. A large throstle-frame cn this principle will be ready and working in about six or nine months.

c

In the engraving, a is a part of the rail which supports the bobbins, and b is one of the bobbins. The bobbin works loose on a stud, which is fixed to the rail a: the stud, together with the rail a, and the bobbin, are shown in section is the rail which holds the top collars of the spindles; and d is the rail into which the foot steps of the spindles are fixed. The two last-named rails are firmly fixed to the framing of the machine, and the rail a is moved up and down by means of a heart motion, to build the thread on the bobbin. The dotted line shows the thread, and the arrows point out the way in which the thread passes to the bobbin. It will now be seen that the stud on which the bobbin works must be a tube, so as to allow the thread to pass through it.

If the flanch on the tube which supports the bobbin was made very large in diameter, the thread would pass on to the bobbin, without the two under hooks on the flyer. tried this plan, and it did very well; except when the bobbin was near the lowest point of its up and down motion. When in this position, the part of the thread at the flanch got so far behind the flyer, that the part of the thread betwixt the top of the flyer and the flanch came in contact with the flanch of the bobbin; but I do not think that this would have taken place, if the flanch on the end of the tube had been made a little larger in diameter.

Yours, &c.

JAMES WHITELAW,

Glasgow, March 16, 1936.

ELECTRO-VEGETATION.
Letter III.

Sir,-In consequence of what has been advanced in my two preceding letters, pp. 99, and 402, concerning the connexion between the electricity of the atmosphere and vegetation, I request the patience of the reader while I take a review of facts, most of which are well known, relative to the peculiar fitness of plants from their structure and properties, and from the nature of the elements by which they are surrounded, for receiving elec. tric influence; more especially, as it was by such general considerations that I was induced to make the experiments which evinced the great superiority of their conducting efficacy to those of all other substances, and which have received such ample additional support from those of Mr. Weekes. The several branches of the subject may be stated as follows: 1st. Amid the immense diversities of the vegetable kingdom, there are several important particulars in which they bear a common relation to electricity. The

solid fabric of a plant, in a state of complete separation from its fluid contents, is a perfect non-conductor, impermeable to electricity; it is every where, in the line of its trunk, branches, and roots, bored with capillary tubes of such extreme minuteness, as to be discernible only by the higher magnifying powers of the microscope. In proportion to its dimensions, its branches and roots are divided into innumerable slender and tapering ramifications, spreading on every side in the

atmosphere and the soil to a wide extent beyond its central stem or trunk; and while the general form of the branches and roots is rounded with a smooth and even polished surface, the former are furnished with buds or leaves which have uniformly acute extremities. Now this is a fabric admirably adapted for the reception of conducting liquids destined to be acted upon by the electricity of the surrounding elements. The dry fabric, itself unsusceptible of electric influence, confines the action of the subtle fluid to its liquid contents; its capillary tubes are exactly fitted to facilitate the rise and diffusion of liquids possessing conducting virtues, by the action of electricity the passage of such liquids through capillary tubes having been proved by the numerous and decisive experiments of the Abbé Nollet* to be greatly increased by electricity in degrees advancing with their minuteness.

:

2nd. That the sap of plants is a powerful conductor, appears from the fact of the superior conducting virtue of the points through which it is influenced; for when these points in common with the rest of the solid fabric are deprived of their liquids, they are destitute of all conducting virtue. This also appears in some degree from the composition of the sap, as it consists chiefly of water and carbonic acid; but its conducting virtue must be much aided in its operation by the minute tubes through which it receives the electric influence. By its action on the sap under such circumstances, in conjunction with those mechanical causes which have been assigned by physiologists, we shall probably be enabled to find the easiest solution of the fact, that the sap advancing through successive stages is mounted to the utmost summit and extent of the loftiest trees. At last, a continued positive electricity, acting probably in those strata which surround the highest trees with the greatest energy, from its distance from the humbler vegetables, and from the uninterrupted motion of the winds at these altitudes, must act in addition to capillary attraction, and the contractile motion which has been ascribed to the tubes in forwarding the general result. I have observed it greatly promoting the

* See Priestley's History of Electricity, pp. 185 -145,

rise of a liquid in strips of porous paper; and strongly incline to the opinion that, as the subtle fluid extracted from oxygen gas in the lungs is the primary cause of the circulation of the blood in animals, to which the structure and mechanical motions of the heart and blood-vessels are only accessaries, so the same subtle fluid in the atmosphere is the primary cause of the rise and diffusion of the sap in plants, to which the structure of their tubes, and the contractile influence to which they are said to be subjected, are likewise only accessaries. The sap, like the blood of animals, contains the materials for the nutrition of the fabric; and the electric fluid introduced from its upper extremities must not only act through the sap-vessels in drawing it upwards, thus promoting the absorption of the moisture from the soil in a state of comparative negation by the fine extre mities of the roots; but, being the general cause of chemical action, it must give rise to those separations and combina tions of oxygen, carbon, and hydrogen, by which, in concurrence with the secretory vessels, the various juices and solids of the plant are produced, and gradually enlarged and matured.

3d. The atmosphere in a state of dryness, or separation from its clouds and vapours, being a non-conductor and electric, is admirably adapted for retaining a portion of the electric fluid, and gradually imparting it to the points of vegetation. Were this element a free conductor, it would at once transmit the electric matter to the earth in a manner so uniform and universal, that an equilibrium would be constantly maintained; but being invested with the opposite property, large portions of it are lodged in it in a state of readiness to be imbibed by those myriads of conducting pipes which issue up almost every where from the earth, and from their peculiar structure convert it to the most useful purposes. So great, indeed, is the quantity of electric matter which is furnished from this mighty electric, that not all these myriads of potent conductors can so far exhaust it, as that some sensible degrees of posi tive electricity are not always discoverable in it, during the day season at least, which is the period of active vegetation. As the electric property of the air in union with its gaseous state brings it in constant contract with the extremities of

plants, so its winds must be of great use in imparting its electricity to the stiff points of the buds and germs. Triturating on these living embyos of vegetation in successive volumes, it must convey to them continually fresh portions of the fluid; thus producing that first excitement of the vegetating principle by which its dormant energies are awakened in the spring season. This influence applies in the greatest degree to the loftier vegetation, where it is most required; but every vegetative shoot, whether from the surface of the soil, or from herbs and plants of every altitude, is finely fitted to imbibe electricity from the strata of airwh which it is contiguous; probably the re dection of the sun's rays from a dry surface of earth on a bright day, affords copious supplies of electric matter to the grasses and herbs as they emerge from it.

4th. Clouds and vapours form another source from whence plants are supplied with electric matter; and their acute extremities are active organs in obtaining this supply. Cold has been generally assigned as the cause of the condensation of vapour; and the peculiar coldness of buds and leaves has been alleged as the reason why it is attached to them in the form of water, in greater abundance than to other substances. But, upon this principle alone, how can we account for the pearly drops which attach so exclusively to the pointed extremities of the grasses, and which appear like rolling orbs upon the cabbage, strawberry, and many other herbs? Grasses in proportion to their length and acuteness are the most potent even of vegetable conductors; and these are the most distinguished for the avidity with which they attract the dew-drops at the approach of evening, and for being the last to part with them as the morning sun advances. the fibrils of the strawberry-leaf, of the alpine wall-cress, &c. he examined with the microscope on a dewy morning, beautiful globules will be seen attaching exclusively to the extremities of the points; in the former, these points are of considerable length, and placed at convenient distances from each other, for the purpose of electric action on the surface of the leaf; in the latter, the arrangement of the points is so curious, that the design can hardly be questioned: numerous upright stems arise every where from the surface of the leaf, branching into four

If