have been examined, and obtained the certificates required by the several sections of this act, shall in the event of loss or damage to property, or injury to persons, occasioned by the breaking of any part of the machinery, or the bursting of the boiler, or boilers, be subject to a fine of not less than nor more than dollars, and an imprisonment of not less than ; and that in event of loss of life being the result of such accident, then said captain, or master, shall be adjudged guilty of manslaughter. nor more than SEC. 18. And be it further enacted, That any boat or vessel propelled in the whole or in part by steam, which shall have its boilers upon the guards of the boat, and shall have between them, and the interior of the boat, or vessel, a sufficient bulwark of timber, or other suitable material, so that passengers shall be protected effectually from injury in the event of explosion, shall be, on a certificate to the foregoing effect from the inspector heretofore provided, exempted from the payment of fees for the taking out of the license of navigation, and shall have remitted one half of the fees for proving and for other purposes of precaution heretofore provided. The fees remitted in such case to be assumed and paid to the respective officers by the United States. SEC. 19.*-And be it further enacted, That for any false certificate, or one given without the thorough examination contemplated by this act, the inspector herein provided shall be dismissed from office, and fined not lessthan dollars, nor more than dollars, and imprisoned not less than i and shall be incapable of ever being re -, nor more than appointed to said office. SEC. 20.t--And be it further enacted, That all penalties, fines and forfeitures imposed by this act, may be sued for and recovered in any court of the United States of competent jurisdiction within the district, or circuit, where the same may have been incurred, in the name of the United States-one half for the use of the informer, and the other half to the use and benefit of the United States. Provided, That all suits, actions, or indictments instituted, commenced, or found, under this act, shall be commenced or found, within two years after the offence has been committed, or the cause of action accrued. FOR THE JOURNAL OF THE FRANKLIN INSTITUTE. Description of a machine for Milling Coin, invented and introduced into the Mint of the United States. BY FRANKLIN PEALE. For the purpose of reducing manual labour, and expediting the processes of the Mint, I was induced, during the latter part of the last year, to make designs for the construction of a Milling machine, to be propelled by the steam power ordinarily employed in the Mint, a model of which I had the honour to exhibit at one of the late conversation meetings of the Institute. From these designs and model, the machines to which this communication relates, have been most satisfactorily executed in the workshops of the Mint, and are now in full operation in the coining department. * Sec. 17th of bill reported, &c. † Sec. 18th of bill, &c., with the addition of the proviso at the close of the section. To those who are unacquainted with Mint operations, it will be well to explain, that the operation of milling has for its object, to throw up a thickened edge upon the blanks or planchets, previous to their being struck, by which means a better border can be given to the coin, with less labour or injury to the dies, it is also, sometimes employed to impress letters or ornaments upon the edge of the coins. A classical tripod, of cast-iron, supports the table on which are placed the feeding tubes and dies; through the centre of the stand a vertical shaft rises from the room beneath, on the lower end of which is a pulley and its band, furnished with a clutch box, by means of which, movement is given, or arrested, as occasion requires. A winch handle may be applied to the hexagonal top of the axis, for the purpose of adjustment, or to propel the machine, if required, by manual force. Upon the central axis is a wheel, furnished with two steel dies upon it periphery, the length of each of which corresponds to the circumference of the coin to be milled; and on the trilateral spaces of the table, are firmly screwed blocks for the outside dies, furnished with the necessary adjusting screws, by means of which the proper degree of pressure is given. Upon the axis immediately above the central wheel, an oval cam, or eccentric, is placed, for the movement of the feeders; this cam is set in time to place the blanks between the dies, when the extremities of the latter are opposite to each other. The feeders are levers, moving on centres, placed on each of the three arms of the gallows which supports the upper ends of the axis; which levers are kept against the cam by spiral springs, contained within a cavity at the centre of motion. A circular blade, or pitcher, as it is technically called, takes the lowest blank from the pile contained in the feeding tubes, and pushes it forward, at the required moment, and a light curved spring prevents its being thrown in advance of the movement. Nearly all of the parts are exhibited in the annexed views. This machine is triplicate, and all its feeders may be put in motion at the same time, or any one of them, as occasion may require. Each division is capable of milling 200 pieces, or more, per minute, equal to 12,000 per hour, with the attendance of a boy only; and during this rapid operation, separates any defective pieces that may pass into the tubes. This machine has been in operation since February of the present year, and has given unqualified satisfaction in every respect. Observations on Microscopic Chemistry. By JNo. W. DRAPER, M. D. Professor of Chemistry and Natural Philosophy, Hampden Sidney College, Va. 1. One of the greatest obstacles to a more general study of scientific chemistry, is a prevailing opinion, that of all the various branches of knowledge, this demands more diversified resources, and entails upon those who prosecute it, an expenditure, usually beyond the means of private individuals. 2. It therefore is the duty of those who wish well to the science they cultivate, to point out the error of such an opinion. Within a few years there has been a complete revolution in chemical manipulation, or the mode of making experiments; a change, to which we are to ascribe the present rapid advance of the science. Operations on the large scale, are never performed, except by those who are public teachers, and here the necessity of rendering effect visible at a distance, calls for a degree of magnitude in experimenting, that unfortunately leads the pupil to conclude, that such pursuits can only be followed by the possessors of large fortunes, and even that they would meet with "almost impossibilities," except they were residents of cities. Those large retorts, and bells, and complicated stop-cocks, and furnaces, the innumerable company of vials, and tests. and electrical machines, and galvanic batteries, could not be purchased in the country. This is a conclusion to which those who have a predilection for these studies are often led, an unfortunate conclusion, for it restrains many a one who would otherwise be an active and efficient labourer in the field. Now, there are few chemists, even among those who reside in cities, and have the disposal of well appointed laboratories, who could not communicate a large stock of highly useful information to their less fortunate brethren. A man, who for a number of years, has been engaged in all kinds of operations of repetition and research, must of necessity be acquainted with a number of simple succedanea, both in the shape of operations and instruments, which at times have obtruded themselves upon his necessities. With this view, I propose to offer my mite, in the hope that it may stimulate others, who are far better able to extend this kind of information. 3. The specific properties of any kind of matter, are as well seen in a small particle as they are in a large mass. A piece of marble, not bigger than a pin's head, will furnish the same chemical results, as a piece of an ounce weight. Hence, if the operator possessed that delicacy, and tact which would enable him to work as well with the small quantity as with the large, his result would be equally striking, and equally true. Like all other sciences, in its infancy chemistry had a degree of roughness, which offers a remarkable contrast with the neatness and finish of modern manipulation; instead of those enormous alembics, and colossal retorts, which dignify the works of the earlier writers, we now give instructions to perform the same distillations in fragments of quill tubes; the blow-pipe has replaced the hundreds of blast, and forge, and reverberating furnaces, over which the alchemist toiled, by the sweat of his brow, not, alas, gaining his bread; and the grain weight and cubic inch have become the units of the laboratory, instead of the pound and the gallon. 4. The manipulation of microscopic chemistry, consists in the art of working with small portions of matter. It requires a degree of manual dexterity which practice alone can give, but which if once gained, is of vast importance to the chemist. It reduces, to an indefinite extent, the charges and expenses he incurs in a series of experiments; and, what is equally valuable, there is a great saving of time. A few minutes will often put him in possession of the same facts, that on the old plan he must have been hours or days in acquiring. Again, there are often circumstances under which he would be compelled to work on minute quantities, as perhaps in the detection of a poison in the stomach, or in the analysis of a precious substance, and here if his previous habits had not accustomed him to operations on the small scale, he would soon find himself quite incompetent to perform his task. In this point of view, perhaps future chemists will hereafter assign a much higher rank to Dr. Wollaston than to Sir H. Davy, the simple, refined and delicate experimenting of the former, affording a more useful guide than the dashing brilliancy of the latter. 5. It is not many years, since the mouth blow-pipe was transferred from the workshop of the jeweller, to the laboratory; it has already become one of our most powerful and useful implements, giving a command over a range of temperature nearly as high as the melting point of wrought iron. Still later the simple candle or lamp has been employed, without any means of urging the flame, and when properly managed, its applications are also very extensive; to the chemical student, it is an invaluable substitute for all kinds of extensive furnaces, and therefore deserves to be thoroughly understood. As there are many parts of the United States, where oil is with difficulty obtained, and lamps scarcely ever used, I propose first to make a few remarks on the power and method of using a tallow candle, as a source of heat. 1 6. The range of temperature that can be commanded by a tallow candle, is by no means inconsiderable; it is well known that iron or steel filings sprinkled on the flame, are made at once white hot. And if a copper wire be presented to it, under certain circumstances, it will be fused in a few moments. This is a simple experiment, but one well deserving of repetition; so far however as I am aware, it has never yet been pointed out; it is striking, and perhaps in the hands of a skilful machinist, might have some useful applications. A thin copper wire, is to be bent into a spiral of six or eight turns, over a cylinder of wood, about the size of a black lead pencil; one end is left uncoiled as at a, to be used as a handle; the spiral is now to be put over the flame of a candle, whose wick has been fresh snuffed; it is to be arranged so as entirely to surround the flame, and held by the extremity a; the flame immediately, burns very dimly, and puts on a greenish hue, and the copper wire melts and falls down. So complete and perfect is the abstraction of the heat from the flame, that I doubt not that if a narrow tube were placed under similar circumstances, and a stream of water forced with great velocity through it, it would be an advantageous mode, if not the most advantageous, of applying flame as a source of heating liquids. 7. A great variety of experiments are required, respecting the fusibility of minerals or other substances, and the characters they display in the fire; these for the most part, may be made by paying due attention to the size of the fragment operated on, viz, that it shall be sufficiently small, and that the support on which it is presented to the flame, be as fine as possible, and of a highly non-conducting material. It is the perfect fulfilment of these conditions, that enables a simple candle flame to burn iron filings. A little |