time, I was a Ship Builder, constructing Boats, the sails of which were set to a side-wind by the vane at the mast head; so as to impel the vessel in a given direction, across a given Puddle, without a steersman. (See Plate 2. Fig. 3.) In fine, I was a Joiner, making, with one tool, a plane of most diminutive size, the [relative] perfection of which obtained me from my Father’s Carpenter a profusion of tools, and dubbed me an artist, wherever his influence extended. By means like these I became a tolerable workman in all the mechanical branches, long before the age at which boys are apprenticed to any: not knowing till afterwards, that my good and provident Parent had engaged all his tradesmen to let me work at their respective trades, whenever the more regular engagements of school permitted.
Before I open the list of my intended descriptions, I would crave permission to exhibit two more of the productions of my earliest thought—namely, an Instrument for taking Rats, and a Mouse Trap: subjects with which, fifty years ago, I was vastly taken; but for the appearance of which, here, I would apologize in form, did I not hope the considerations above adduced would justify this short digression. If more apology were needful. … Emerson himself describes a Rat-trap: and moreover, defies criticism, in a strain I should be sorry to imitate! my chief desire being to instruct at all events, and to please if I can: without, however, daring to attempt the elegant Problem, stated and resolved in the same words—“Omne tulit punctum, qui miscuit utile dulci.”
The town of Cirencester (my native place) is intersected by several branches of the river Churn, whose waters are pure and transparent, and whose banks, formerly, were much perforated by the industry of the Rats that had made them their residence. These holes had generally two openings; one at or near the surface of the ground, and the other near the bottom of the river: so that the rats could range the fields from the former, and dive into the water from the latter—where they were often seen gliding along the bottom, either up or down the stream. The Instrument for taking them in these circumstances, was no other than my Father’s Walking-stick, (represented at A. Fig. 1. Plate 2.) connected with the curve B by the joint C; the curve having a string fastened to it, which, passing through the body of the stick, rose to the hand at D, for the purpose of closing the fork at the proper moment. The Machine, thus constructed, was put over the rat’s back while in the act of diving; and by pulling the string C D, he was sufficiently pinched to be drawn out of the water, where a Dog stood ready to dispatch him.
On the Mouse-trap (Fig. 2. and 4.) more thought was bestowed. It appeared adviseable (I remember) to lay the deceptive plan rather deep: and to lull the little animal into a false security till the snare had taken full effect; and even then to hide from her some of its horrors till she was far enough from this vestibule of misery, not to deposit there any of those tokens of distress that might deter other mice from following her example. The trap then, consisted of a long passage, formed spirally round the surface of a Cone, like the figures we have of the Tower of Babel. This passage is uncovered in Fig. 4 to shew the entrance E, and the subsequent gates F G H, &c. which like the valves of a pump, gave easy entrance to the victim, but forbade her return. At the length of a mouse from the outer gate E, was placed the first bait N, say a small rind of cheese, well toasted to allure, but nailed down to prevent its removal. Its position was further indicated by a train of meal reaching from it to the outer gate E; which latter was nicely hung on pivots inclined a little to the perpendicular, so as to open with ease but never fail to close itself again. It had besides an horizontal plate O, fixed to its bottom on the inside, so that if the mouse attempted to open it that way, she trode on this plate and destroyed the result of her own efforts.
When, therefore, the little wretch had passed this barrier, she was in reality taken: but unconscious yet of danger, she nibbled the first bait with pleasure, and then skipped forward in search of more substantial food: but to obtain this she must pass more of these faithless gates, F G H, &c. which with progressive effort she opened, and at length found the inner compartments replete with good things, on which she fed to satiety, and then only began to think of her situation. Nor yet, with much alarm: for at the end of this labyrinth, so easy of access, she hoped to find an easy exit. But alas, these hopes were illusive. Instead of light, she found the dark gallery O; the least evil of which was to be too narrow for two mice abreast, since it overhung a tremendous cavern, Q, that entirely occupied the Cone below, and was filled with water deep enough to drown her, were she to fall, or be jostled into it. And one of these disasters she could hardly escape! for other mice would not fail to be beguiled into this cruel Bastille; to reach the same spot; and finally, to plunge her into this watery grave.
Having endeavoured to recollect the substance of these youthful attempts to unite cause and effect, or to fulfil a given purpose by preconcerted means, I now turn to things of greater importance, and more worthy to be the theme of my readers’ attention. The subjects to be presented will observe a miscellaneous order; since they have not only originated at different periods, but offer likewise different degrees of interest—to equalize which throughout the Work, appears a desirable attempt. As to the manner of treating each subject, it will be, generally, to describe the Machines by a reference to the Figures; and then to add some remarks on their date, construction, properties, and uses.
PART FIRST.
A NEW CENTURY OF
Inventions.
A
DYNAMOMETER;
OR,
Machine for measuring Power and resistance while in Motion.
Dynamics being a science that relates to bodies in motion—comprehending not their weight only, or their velocities only, but the product of the one by the other; so the Dynamometer is a mean of measuring both these circumstances together, and thus of making known the momentum of a power or resistance in motion. As this Machine has a connection more or less intimate with almost every other, it seems entitled to the first place in this collection. Its description follows:
In Plate 3, Fig. 1 and 3, M M, represent two cheeks, standing parallel to each other, and forming a cage or frame by means of the cross bars E and the nuts F G. A P, Fig. 2, is the principal axis of the Dynamometer, fixed to the wheel R N of which it is the centre of motion. It has a square end A, formed to receive the wheels and other supplemental parts, to be mentioned below. After the square A, comes a bearing E, to fit the steps in the frame; and beyond the wheel R N is a cylindrical part O, fitted to the hollow axis T of the wheel or frame I K, (Fig. 4); and in fine the form P of this shaft fits and turns in the cannon of the axis B H, of the wheel C D; so as, when put together and connected with the frame I K, to assume the form C R F G of the third figure. L P, Fig. 3 and