PIRACY OF TRADE-MARKS.

"Thus, then, it follows, that the strongest form of section in a cast-iron beam is that

Dec. 21.

Baker v. Cole.

Mr. Dixon, for the plaintiff, William Baker, moved ex parte for an injunction to restrain the defendant, Richard Cole, from using the trade-mark or name of " Impilia" upon the sole of any boots or shoes sold by him, or by his direction, and from selling any boots or shoes with that trade-mark or name thereon, or any boots or shoes made according to the plaintiff's patent.

The plaintiff's affidavit stated that he had discovered a new and useful invention for an improvement in the manufacture of boots and shoes, for which, in January last, he had obtained a patent, and had, in July, enrolled his specification. The invention was specified to be "the applying a piece or sole of matted or felted horse or other strong curled hair between the inner and outer sole of the boot or shoe." The plaintiff had designated the articles thus made by the name of "Impilia," which name had become universally known as designating his boots, and never had been before so used; but he had caused it to be adopted as the trade-mark of the boots and shoes made according to his patent. He discovered on the 17th instant, that the defendant was selling boots and shoes which he represented to be "Impilia" boots, &c., made according to the plaintiff's patent, excepting that instead of horse-hair there was wool placed between the soles. The defendant had sold to a man of the name of Wise a pair of these boots, with the word "Impilia" upon the outer sole.

Injunction granted.

MOSELEY'S MECHANICAL PRINCIPLES OF ENGINEERING AND ARCHITECTURE.CONCLUDING NOTICE.

The theory of rupture by transverse strain is illustrated by a new class of problems, having reference to the forms of beams with wide flanges, connected by slender ribs, which will be found fraught with useful practical instruction. But here, again, the reader will not fail to be forcibly struck with the subordinate part which the mathematician plays, compared with the experi menter. For example :

unequal flanges, joined by a rib, the greater flange being on the extended side; and the proportion of this inequality of the flanges being just such as to make up for the inequality of the resistances of the material to rupture by extension and compression respectively. Mr. Hodgkinson, to whom this suggestion is due, has directed a series of experiments to the determination of that proportion of the flanges by which the strongest form of section is obtained. The details of these experiments are found in the following table:

"In the first five experiments, each beam broke, by the tearing asunder of the lower flange; the distribution by which both were about to yield together-that is, the strongest distribution-was not, therefore, up to that period, reached. At length, however, in the last experiment, the beam yielded by the compression of the upper flange. In this experiment, therefore, the upper flange was the weakest; in the one before it, the lower flange was the weakest. For a form between the two, therefore, the flanges were of equal strength to resist extension and compression respectively, and this was the strongest form of section. In this strongest form, the lower flange had six times the material of the upper. It is represented in the accompanying figure.

"In the best form of cast-iron beam or girder used before these experiments, there was never attained a strength of more than

2885 lbs. per square inch of section. There was, therefore, by this form, a gain of 1190 lbs. per square inch of the section, or of ths the strength of the beam."-Page 558.

It is only in the case of cast-iron beams that it is customary, by varying the form of the section, to effect a saving of material; but Mr. Moseley sees no reason, as neither do we, why the same principle of economy should not be equally applicable to beams of wood.

The following general enunciation, by the Professor, of the conditions requisite to the production of a "solid of the strongest form, with a given quantity of material," is one of the happiest, because clearest and most intelligible, in the whole work.

"The strongest form which can be given to a solid body, in the formation of which a given quantity of material is to be used, and to which the strain is to be applied under given circumstances, is that form which renders it equally liable to rupture at every point; so that when, by increasing the strain to its utmost limit, the solid is brought into the state bordering upon rupture at one point, it may be in the state bordering upon rupture at every other point. For, let it be supposed to be constructed of any other form, so that rupture may be about to take place at one point when it is not about to take place at another point, then may a portion of the material evidently be removed from the first point, without placing the solid there in the state bordering upon rupture, and added at the second point, so as to take it out of the state bordering upon rupture at that point; and thus the solid, being no longer in the state bordering upon rupture at any point, may be made to bear a strain greater than that which was before upon the point of breaking it, and will have been rendered stronger than it was before. The first form was not, therefore, the strongest form of which it could have been constructed with the given quantity of material; nor is any form the strongest, which does not satisfy the condition of an equal liability to rupture at every point.

"The solid constructed of the strongest form with a given quantity of a given ma. terial, so as to be of a given strength under a given strain, is evidently that which can be constructed of the same strength with the least material; so that the strongest form is also the form of the greatest economy of material." Page 533.

We must now bring our rather extended

(yet very imperfect) examination of this generally most valuable work to a close; but before doing so, we must advert briefly to what we consider its chief defects.

In the first place, we must state our strong impression, that it is by far too learned for the classes (Engineers and Architects) for whose use it is specially designed. To be read and understood with ease, it requires that the reader should be master of all the arts and even refinements of mathematical analysis, and that is more, we fancy, than one in ten of the respectable classes (excellent practical men, notwithstanding) can pretend to be.

In the second place, the learning is not seldom of rather a superfluous character; showing, it may be, great proficiency and skill on the part of the author, but calculated to be of no practical service.

And, in the third place, the author, in his fondness for theorizing, forgets, occasionally, how essential it is to every sound theory, that it should be based on facts.

We may cite, as a striking example of all these three defects, the whole of the section on that very simple and useful agent in machinery, the band. Every mechanic knows that the best arrangement for communicating the motion of one shaft to another through the medium of a band and drums, is to apply the moving and working pres sures on the same side of a vertical line passing through the axes of the two drums: every mechanic knows too, that a band is worked to most effect when the two portions of the band between the drums are made to cross one another. Neither can any mechanic of common intelligence be at any loss for the causes of both results-namely, the parallelism of the pressures in the one case, and the greater portion of each drum embraced in the other. Effects and causes so well known, and so obvious as these, might, with propriety, have been disposed of by a simple enunciation; but our very learned Professor must needs demonstrate them mathematically, and in doing so puts one forcibly in mind of Swift's definition of this sort of scholastic accomplishment-namely, that it is "the putting a number of queer looking things through

number of very queer manoeuvres in order to place them just as they were." The reader sees a multitude of strange signs and symbols paraded before him, and much disposing and transposing of the motley group, till the whole are arranged into a certain number of squares (called equations) by which he is given to understand, that that which he knew to be true before, is rigidly demonstrated after the most approved Cambridge fashion. He admits it may be so, but wonders that Cambridge people should put themselves to so much trouble to no purpose. He can see too (being, as we suppose him to be, a practical man,) that amidst all this display of mathematical skill, there is at bottom but an imperfect acquaintance with the thing itself, which is the subject of it. Take, for example, Mr. Moseley's demonstration of a certain principle said to have been first promulgated by Poncelet, and amply confirmed by the experiments of Morin, that "the sum of the tensions upon the two points of a band is the same whatever be the pressure under which the band is driven, or the resistance overcome, the tension of the driving point of the band being always increased by just so much as that of the driven point is diminished." Neither Poncelet nor Morin has given any demonstration of this principle; Mr. Moscley does, and in these words :

"In the very commencement of the motion of that drum to which the driving pressure is applied, no motion is communicated by it to the other drum. Before any such motion can be communicated to the latter, a difference must be produced between the tensions of the two parts of the band sufficient to overcome the resistance, whatever it may be, which is opposed to the revolution of the driven drum. Now, an increase of the tension on the driving side of the band must be followed by an elongation of that side of the band (since the band is elastic), and by the revolution of the circumference of the driving drum through a space precisely equal to this elongation. Supposing, then, the other, or driven side of the band, to remain extended, as before, in a straight line between its two points of contact with the drums, this portion of the band must evidently have contracted by precisely the length through which the circum

ference of the driving drum has revolved, or the driving side of the band elongated. Thus, the elongation of the driving side of the band is precisely equal to the contraction of the driven side. Now, the band being supposed perfectly elastic, the increase or diminution of its tension is exactly proportional to the increase or diminution of its length. The increase of tension on the one side, produced by a given elongation, is therefore precisely equal to the diminution of tension produced by a contraction equal to that elongation on the other side."-Page 234.

The supposition on which this demonstration rests, that a certain contraction takes place on the driven side of the band, every practical man must at once pronounce to be a great mistake. Contraction there is none, and can be none. If there were, there must be some contracting force; but where is it? The only active force in the case is the driving pressure, but that could not both elongate and contract the same band (even on the opposite sides of a drum,) at one and the same time; to suppose so, would be to suppose a mechanical absurdity. The one side of the band is elongated (tightened) more than the other, and it may be that the degree in which the one side is elongated is exactly proportional to the degree in which the other remains of its original length; but to say that a band is contracted, because it is not more or less elongated, is an obvious misuse of language. That the degree in which one side is elongated is in reality exactly proportional to the degree in which the other remains of its original length, though probable, is by no means certain; for it is a fact familiar to all persons who have any thing to do with bands and drums, and one which renders Mr. Moseley's demonstration still more inadmissible, that it often happens that the tighter the driving side of a band is, the slacker is the band on the driven side.

We promised, when noticing the section of the work which treats of Friction, to give at length the excellent Tables by which it is illustrated; but we find that our present limits will only allow of our annexing that which exhibits the "friction of plane surfaces in motion one upon the other." It is, however, by far the most valuable of the whole.