GILMAN'S REPLY TO A down an inclined plane. But in conveying loads up an inclined plane, the additional weight arising from the friction-wheels would increase the gravitating power of the load. With the common cars, as perfected in England, the horse could draw up a plane inclined 30 feet per mile, only onehalf as much as he could draw on a level; because, as before stated, the effect of gravity would there be just equal to friction, computing the latter at T of the load. Now, if the car of Mr. Winans enables the horse to draw 56 tons on a perfectly smooth and level road, where friction only is to be considered, it would require the strength of about 7 horses to convey the same load up the inclined plane just mentioned. This would seem to decide in favour of confining the use of this car, if adopted at all, to level roads, or to those on which the transportation is descending, or at least to those on which stationary power is employed in surmounting elevations. As the invention has been presented with a request that its merits and defects may be closely scrutinized, your committee have thought proper to present some of those points in which it seems likely that this carriage may be found inconvenient, or defective, in its practical application. The first of these arises from the shortness of the axes of the secondary wheels, compared with the diameters of those wheels themselves, by which they will be liable to act as bent levers, and twist the side pieces of the frames out of their natural positions, or to wear, unequally, the two bearings of those axes. Second. The latter effect will, it should seem, be increased by the swagging of the load from side to side, in consequence of the arrangement by which the ends of the axes of the primary wheels act against the flanches of the secondary. Now they always act outward, and on one wheel at a time for each axis; consequently, there can be no restoring tendency, by which, when a friction-wheel is pushed out of its vertical position, or its inner bearing is worn more than the other, the evil will be likely to be corrected. Third. The imperfection of castings and other workmanship, may possibly allow the friction-wheels to be worn in one or more places on the inside of each rim, to such a degree, as to allow the gudgeon to turn in the hollow part, as in a common bearing, and thus to prevent the secondary wheel from revolving. Should this be the case, the friction would, for that gudgeon, be reduced to that of the simple car. Fourth. The friction-wheels must be made heavier than if the pressure of the primary axles were applied to the outside of their rims: because, in the latter case, the arched form of the part to which the pressure is applied, would conspire with the cohesion of materials to prevent the fracture of the rim, but the cohesion of parts must alone sustain the pressure in the case of the car at present under consideration. Finally, as the axes of the primary wheels do not constantly preserve their parallelism with those of the secondary, the gudgeons of the former may be irregularly worn, in consequence of the obliquity which they may assume to the cylindrical surface of the interior of the friction-wheel; and the same circumstance also allowing the whole pressure of a gudgeon to be occasionally brought upon the edge of the rim of a friction-wheel, this part must be made strong enough to sustain the whole weight. In conclusion, your committee would express a wish to see a carriage on this construction of full size put into operation, believing, that on levels and gradual descents, at least, it may be found eminently serviceable; and not doubting, that the same ingenuity which devised the construction, would supply the defects which we have pointed out, should they prove to exist, or any others which experience might demonstrate to belong to the peculiar construction now exhibited. All which is respectfully submitted. some darling project, destroyed some golden harvest expectant. Smarting under the feelings excited by its perusal, he appears to have hastened to explore every patent which has the smallest bearing on the subject; but seeing things only through a distorted medium, he has discovered nothing but analogy, where in all probability none exists. I have seen one only of those patents to other parties, which he enumerates, and nothing in that bears the least analogy to my plans. With respect to the old patent in which my own name appears, when all is made known in regard to the share I had in its formation, a very sufficient reason will be unfolded for my making no reference to it in the paper which has provoked the ire of the Practical Engineer." But if the existence of that patent proves my want of candour, how will this worthy stare when I inform him that there is yet another patent that has escaped his search -which was sealed while the apparatus which has vexed him so much was in operation and yet, strange to say, it contains no allusion to the plans in dispute! Before, however, indulging the "Practical Engineer" with any explanation of these things, I must first call on him to put in an appearance, as the lawyers call it, by subscribing his real name and address in the "Mechanics' Magazine." We shall then meet upon equal terms. Had he been honourably disposed, he would have done this at once, and ren. dered this request unnecessary. I care not, friend "Practical," who thou art ; only come forth in thine own proper person, and I will balance accounts with thee, item by item, when we shall see on which side the want of candour lies. I will just, in the mean time, observe generally, that it never was pretended that the apparatus in question was perfect, or of the best form for general use; and perhaps I know its defects quite as well as this man of wisdom, who, with all his practical pretensions, treats of imperfections which never existed. The apparatus was ar aged solely for our then purpose, and ther defective or otherwise, is of no Dortance to the question at issue; it es not in the least affect the principle was designed to illustrate-which principle indeed is left wholly untouched by any thing the "Practical Engi has advanced. I could have red many drawings that perhaps A PRACTICAL ENGINEER." this" Mr. Errorless"* would say were not objectionable; but if I had taken either of them instead of the one that was really executed, merely on account of these blemishes, for the Magazine, then perhaps I might have been justly charged with a want of candour. Even that however would not have warranted Mr. Practical's" unjust attack, as it would neither have altered the principles of the plans, nor changed the time when those principles were conceived. But the joints! Aye, the joints. Did he never see such a joint? Perhaps not. What a pity! Has he ever seen any thing of high-pressure steam? Perhaps not, also. I will tell him thus much, that when I want a cast-iron joint particularly sound, and when circumstances will permit, whether that joint be square or circular, I never trust to cemented flanges; and farther, that the parts in contact to form my joints seldom exceed three-eighths of an inch wide. In this case they were not one-half of that width, and I can show a hundred as sound as if they were solid metal. But the bolts-even the bolts too, were really sufficient to confine and actually did confine steam of between two and three hundred pounds per inch, and keep sound joints too; and strange it would have been, in my opinion, had they not. So much for "Practical's" experience; but I have forgot the pipes. Aye, they are uncovered and oxidising, and I must hasten to a conclusion. Did THE NOVELTY's" sore place suggest this idea? I believe "Practical" says something about my intention of blowing up" THE NOVELTY," aiming a blow at it, or something of the kind. Indeed, I should have suspected him to have been one of those" wot drive THE NOVELTY," had not his bitter acrimony, his false-coloured and vindictive rigmarole, convinced me that it is far beneath any thing that the proprietors of that engine would descend to. When we meet again, friend" Practical," we will say something more on this subject -and likewise on poor carbonic acid, &c. Now, Mr. Editor, to conclude-had this "Practical Engineer" wished for information, it would have been furnished with great pleasure, either through the medium of the "Mechanics' Magazine," or privately, if he de "Thou perfect soul, drawn by the gods in council, Which they were long in making. THE ADVANTAGE OF cast-irON BRESTSUMMERS. sired, and bad applied in a proper way, Jan. 4, 1830. Your humble servant, P. S.-I hold it to be a sacred duty of an Editor to allow both sides of a question to be heard without favour to one or the other; and I should have been much disappointed in my opinion of the Editor of the "Mechanics' Magazine," if he had not done as he has in regard to the present matter. Allow me, however, to say thus much-that I think so long as the question is conducted in a fair and honourable manner, it matters not whether the disputants appear under their own or under assumed names; but when either descends to acrimonious invective and personality-which is not argument, only a proof indeed of conscious weakness-then you ought to exercise your editorial power, and not publish without name and address. This, in my opinion, is but justice; otherwise, any malevolent fellow may raise a storm that may cause a great deal of trouble, and perhaps injure a man's character-while shielded under an assumed name, he can never be identified, and therefore made to suffer the penalty due to his baseness. As the call made by Mr. Gilman on a "Practical Engineer" to come forward in his own proper person, implies a censure on ourselves for permitting him to enter the lists with his vizor down, and as Mr. Gilman indeed has lectured us pretty sharply in his P. S. on the subject of inserting anonymous communications, (admitting, strangely enough, all the while, that we could not, in the present instance, have done otherwise than we have done,) we must be excused for subjoining a few words on the subject. When a person comes forward, like Mr. Gilman, partly in the character of a patentee, and partly in the character of a public benefactor, to claim the credit of having invented A fact.-EDIT. M. M. 351 something useful to society, with whom is he supposed to deal on the occasion ? Is it not with the public, from whom he hopes for a reward, in some shape or other, for the service he has rendered? And is not the name of that public→ LEGION? As these questions, we apprehend, admit of affirmative answers only, we hold that it matters not a jot which individual of that public it is, A, B,Y, or Z, who undertakes the task of investi gating the originality and usefulness of the invention in question, or whether he comes forward in his real or in an assumed name. It is sufficient, in our opinion, that he is one of that public, to whom the invention is offered, and from whom an adequate return for it is expected by the inNeither can the manner in which a person executes such a task furnish any solid objection to his being heard. The worse the manner of the attack, the better for the individual attacked. ventor. The strictures of the "Practical Engineer" who has acted the part of public censor, in the present instance, did appear to us, we confess, to be couched in language unnecessarily harsh; but they exhibited, at the same time, too formidable an array of facts (seeming facts at least) to allow of our refusing them a place, merely because they happened to be not quite to our taste. Mr. Gilman seems well disposed to leave his opponent nothing to boast of on the score of courtesy; but in this we humbly presume to think he acts not very wisely. Strong words are best replied to by strong reasons. He may rest assured, that he has but one prudent course to take, and that is, not to stand on conditions (least of all on the foolish one about the name of his assailant), but to grapple at once with the facts of the case.-EDIT. M. M. 352 THE ADVANTage of cast-IRON BRESTSUMMERS. or a remedy can be thought of, I am convinced Mr. Baddeley will be amongst the first to give it his consideration. I will therefore venture to give a hint. The very great strength of wrought-iron as a tie is well known. Its use in suspension-bridges, and to strengthen or truss wooden beams, may be mentioned. Indeed, the great advantages of its application to the latter, has led to the idea that it may also be used both to strengthen castiron beams, &c., and to render brestsummers of that material perfectly secure. But this is not all, cast-iron girders, &c. thus supported need not be so heavy; and, indeed, I am not without hopes that beams built of brick and Roman cement may be so effectually supported by wrought-iron ties, as to enable them to carry a considerable load. And if beams can be made of brick, so may the whole of a floor. I am aware brick arches have been turned between cast-iron girders; but I do not know that any attempt has yet been made, although I see nothing to prevent the principle being carried from wall to wall over any moderate-sized apartments, so as to construct fire-proof floors, or even roofs, at the least possible expense. Cast-iron abutments may be placed upon the walls, and the tie-rods may be about a foot apart. If the room be 20 feet wide, the splay of the abutments may be in the direction of a radius that will describe an arc with a rise or versed sine of 6 inches. This arch being constructed of 9-inch brick-work, on the principle of a jackarch, we may have a brick ceiling and floor nearly level. A rise of about 2 inches in the middle of the ceiling is recommended. The iron ties may be so much above the spraying of the arch or bottom of the abutments, as to be entirely (say an inch) within the bricks at the middle of the ceiling. Instead of sleepers, joists, and ordinary flooring-boards, I should recommend thick or plank floors only, ploughed and tongued together, and fastened to the brick-work. The wooden floor should be laid in the direction of the iron ties. I may just notice here that I am glad to observe Mr. Baddeley has turned his attention to the new police men, as the persons from whom the greatest benefit is to be derived in the event of fire. As far back as vol. ix. p. 163, I ventured to express a doubt of the utility of a double set of nightly watchers, or both watchmen and the men to be trained by the "Society for Preventing the Loss of Life by Fire." The observations then made were under the old state of things; but under the new such remarks will be the stronger. I remain, Sir, &c. J. S. S. MISCELLANEOUS.' Perkins' Steam-Cannon.-The first experiments made with Perkins' Steam-Cannon at Vincennes, near Paris, were not attended with very brilliant results; and it appears that the last have not been more fortunate. The enormous apparatus of which this machine is composed was placed at about forty paces distant from a wooden figure formed to represent the hull of a man of war; the projectiles thrown were about four pound calibre, and remained fixed in the thickuess of the wood: a four-pounder was afterwards fired off at the same distance, and the ball penetrated the figure. Other experiments may possibly give different results; but even allowing that the superiority of Perkins' cannon becomes perfectly established, the complication of the machinery and its enormous proportions will render its application to the arming of ships almost impossible.-Journal du Commerce; United Service Journal, January, 1830. It would seem then after all, that the Duke of Wellington was not so far wrong in pronouncing that Mr. Perkins' cannon would never answer. Astronomical Phenomenon.-On the evening of Sunday last, the Moon was distinctly seen at Tynemouth with the naked eye 37 hours after the change a very extraordinary circumstance in this country. Some of the oldest seafaring men declare they never saw the phenomenon before.-Globe, Jan. 3. . INTERIM NOTICES. As the Inquiry which was commenced in the last Session of Darliament into the evils of the Patent Laws will doubtless be resumed on the re-assembling of Parliament next month, and it is of the utmost importance that all who are engaged in mechanical pursuits, or who take an interest in mechanical improvements, should be in possession of the Minutes of that Inquiry, as far as it has yet proceeded, we propose to give an abridgment of the same in small type in a Supplementary Number next week. J. G. N. very acceptable.' Communications received from Mr. Sadding- LONDON: Published for the Proprietor, by M. SALMON, at the Mechanics' Magazine Office. No. 115, Fleet Street'; where Cominu nications for the Editor (post paid) are requested to be addressed. M. SALMON, Printer, Fleet Street. |