The troughs are piled up in a chamber which is heated by hot air or by steam. The vinegar is vaporised by the heat of the chamber and the carbonic acid arises from the fermentation of the lees. Great care is taken to exclude the atmosphere as far as possible, as it is found to injure the quality of the white lead, a point in which this process differs materially from those of Clark and Richards. The product is the finest quality of white lead in Europe, known as the Kremser white. The introduction of carbonic acid, generated by the combustion of charcoal, for the purpose of assisting in the formation of white lead, has been practised many years in France in the new method of precipitating cabonate of lead; it has been farther employed in England, and in this country, in the manufacture of white lead. The novelty of Clark's process therefore consists in forcing atmospheric air into the lead chamber; Richards' in the introduction of steam in addition to the preceding; and both possess some claim to novelty in the peculiar arrangements of their apparatus. The committee cannot draw conclusions relative to the economy of Clark's process nor to the quality of the material produced, as no theoretic grounds will warrant their so doing, but their views on this subject are given more at large in a report on Richards' method published in the July No. of the Journal of the Institute for 1839. By order of the Committee, Philadelphia, April 9th, 1840. WILLIAM HAMILTON, Actuary. Report on Mr. John P. Bakewell's Safety Valve. The Committee on Science and the Arts constituted by the Franklin Institute of the State of Pennsylvania, for the promotion of the Mechanic Arts, to whom was referred for examination a self acting Safety Valve, invented by Mr. John P. Bakewell, of Pittsburgh, Pa., REPORT: That Mr. Bakewell represents his invention to consist in supporting the fulcrum of the lever of the common safety valve in such a manner that the more it may be loaded, for the purpose of keeping the valve closed, so much the more effective it will be in opening the valve, in case the boiler should become unduly heated. To effect this object he makes use of a fusible alloy placed in a tube in the manner recommended some years back by Prof. A. D. Bache. (See Journal Franklin Inst., Vol. X, p. 223.) The stem inserted in the fusible metal, supports the longer arm of a hori zontal lever of the first order, the fulcrum of which is fixed in a standard rising from the valve case and extending some distance above the lever, for a purpose to be named presently. The shorter arm of this lever (which for the sake of convenient reference, we shall term the sustaining lever,) carries a short upright bar, on the upper end of which is the fulcrum of the safety valve lever; the latter being a lever of the second order loaded near its extremity in the usual manner. While the fusible metal remains solid, it keeps the stem and sustaining lever steady, and the apparatus acts precisely like the common safety valve, the loaded lever resting parallel to, and a short distance above, the sustaining lever. But if the metal should be fused by overheating, the stem sinks into it; the short arm of the sustaining lever rises and elevates the fulcrum of the valve lever, the loaded end of the latter descends until the lever comes in contact with a shoulder on the standard before mentioned. This shoulder now becomes the fulcrum of the valve lever, converting it into a lever of the first order, and the action of the weight with which it is loaded now tends to raise the valve with as much force as it previously exerted in keeping it down. The valve is by these means forced open, and, in the opinion of the inventor, will remove all danger of explosion by giving vent to the steam. Without undertaking to discuss in this place the propriety of making an opening at such a juncture, the Committee take pleasure in expressing a favorable opinion of the contrivance proposed by Mr. Bakewell, for effecting that object. So far as appears, the arrangement is entirely novel, it is certainly very ingenious, and combines great simplicity with entire efficacy in opening the valve whenever the alloy is fused. By order of the Committee. Philadelphia, April 9th, 1840. WILLIAM HAMILTON, Actuary. Description of the Self-acting Safety-valve, invented by MR. JOHN P. BAKEWELL, of Pittsburgh. Furnished by the inventor. The invention consists in a mode or method of fastening and securing the pivot end, or turning point, of the beam, or lever, of a common safety valve, in such a manner that the heavier the weight may be which is placed upon the opposite or long arm of the lever beam, for the purpose of keeping the valve closed-the more certain and effectual shall be the operation of the apparatus in opening the valve, whenever the boiler shall have been heated to such a degree of temperature as may be considered dangerous, or liable to become so; which may be done as follows, and is best explained on reference to the accompanying sketch or drawing of the same. A, a metallic pipe or tube, which is to be placed within and securely fastened to the boiler with its lower end resting upon the flue, (or the bottom of the boiler if made without flues.) B, a metallic rod or stem, constructed with an enlargement at one end, and connected, with a right and left screwed collar, to a piece made with a pivot hole at D. E, the safety valve, made as usual, GKL lever beam. F, a suitable quantity of the fusible metallic compound enclosed in a thin metallic cup, which is loosely connected at the top with the rod B, so that it can be taken out of the pipe A, if required, by raising the rod. ST, a bent lever connected at L with the short end of the lever beamturning in a slot at M, and connected with the upper part of B at D, and having an opening through which the stem of the safety valve passes freely without touching. M, a standard or upright attached to the upper casing of the safety valve, and constructed with a slot to admit the free motion of ST, and with cheeks or guides above, which loosely clasp the lever beam; the bottom of which slot is filed to an edge, and is to be about one-half an inch below the bottom of the lever beam, as seen just below n. It will be seen that the fusible metal will sustain the rod B and lever ST, as long as it shall remain unfused, and consequently serve as the support for the pivot end of the lever beam, GKL. And that as soon as it becomes fused, it will allow of the descent of the rod B, and as soon as the lever beam touches the standard M at n, the action of the lever is reversed, and it must exert the same power to open the valve as was before exerted in holding it down. To replace the apparatus, it will be requisite that whenever notice is given from the escape of steam that the boiler has become so much heated as to fuse the alloy-that the engineer should raise the lever beam by means of the usual lift line V, until it touches a bolt or pin P, which is passed through the cheeks of M, and at the same time withdrawing the stem from the melted alloy, and holding it there until the alloy is sufficiently cooled, either from the escape of steam or from cold water having been poured within the pipe A, so as to enable it to sustain the stem as at first. The double right and left screwed collar is intended for the purpose of regulating the proper position of the lever ST, and connexion at L. The claim as inserted in the patent is as follows, viz: "I claim as my invention, the attachment of a rod or stem (B) to the end of the lever or beam of a safety valve, in such a way, that it shall be the fulcrum, pivot, or turning point of the beam, as long as the alloy remains unfused; and, I claim the placing of a standard or upright (M) between the safety-valve and the weighted end of the lever to which the beam shall shift its fulcrum or pivot whenever the alloy shall become fused or melted." The patent is dated December 21, 1839; application filed in September. Mechanics' Register. LIST OF AMERICAN PATENTS WHICH ISSUED IN APRIL, 1839, 1. For an improvement in Church and other Bells, and in hanging the same; Ebenezer Dewey, city of New York, April 10. This bell is a cone, a section through the axis of which would present a right angle at its apex, its diameter at its base being equal to twice its height. "The diameter at the mouth of the bell is forty lines, and the thickness of the lip is one line, and one third of a line in thickness at the top, and half a line in thickness at one third the distance from the base or mouth to the crown, and gradually diminishing in thickness from thence to the crown." These dimensions, it is said, may be changed. This bell is not intended to swing like the ordinary church bell, but it is attached to a cross timber which hangs on gudgeons at its ends to allow a free vibration and motion to the bell. The hammer strikes on its outside, its handle being affixed to a shaft which turns on gudgeons, and which stands parallel to, and above the timber by which the bell is suspended; this shaft has a pulley on its end to which the bell rope is attached, and in ringing, the hammer may be carried clear over from one side of the bell to the other. A spring on each side serves to hold the hammer clear of the bell after the stroke. Claim.-"I claim the gradual diminution of the thickness of the sides of the conical bell from the lip at its base to its apex or crown, in the manner above described; and also the combination of the yoke and shaft containing the hammer handle and the spring, in the manner and for the purpose above described." 2. For an improvement in the Manufacture of White Lead; Charles Button, of Great Britain, and Harrison G. Dyar, a citizen of the United States, April 10. This invention is divided into three parts, consisting, first, of a method of purifying the gases and vapours arising from anthracite, stone or mineral coal, or from coke, so that the gases arising from such kinds of fuel may be used in the manufacture of white lead; secondly, in the use of basic nitrates of lead, for making carbonates of lead, and lastly, in manufacturing white lead from litharge, massicot, or protoxide of lead, by boiling nitrate of lead with either of those substances, and submitting such mixture while in a heated state, to the action of carbonic acid gas. The patentees describe the apparatus employed by them, but do not claim this as making any part of their invention. In the London Journal of Arts, vol. xiv, conjoined series, p. 383, there is an account of this patent, as obtained in England, accompanied by a plate showing the apparatus used. The claims made are, "1st. The acting upon the vapours or gases, arising from the furnace used in the process of making white lead, in such a manner, (by the introduction of atmospheric air, and by washing, hereinbefore described,) as enables us to use that cheap kind of coal, called stone or mineral coal, in the said furnace, and to arrest the smoke and other impurities injurious to the colour or quality of white lead, so that we are enabled to use carbonic acid gas, obtained therefrom, in the process of manufacturing white lead. "2d. In the manufacture of white lead from such compounds of nitric acid with oxide of lead, in which the quantity of oxide bears a greater ratio to the nitric acid combined therewith, than the oxide of lead bears to the nitric acid in the ordinary nitrate of lead of commerce; and which nitrates we call basic nitrates of lead. "3d. Making white lead by boiling, as hereinbefore described, or otherwise acting upon the litharge, massicot or protoxide of lead, with either nitric acid or the common nitrate of lead of commerce; and while in a boiling state or otherwise, submitted to the action of, or brought minutely into contact with carbonic acid, in order to produce a pure carbonate of lead; or, as it is usually called, white lead; and in such manner, that the same nitric acid or nitrate of lead may be used over and over again, many times, with fresh portions of litharge, as hereinbefore described. 4th, and lastly. The process of further purifying and condensing the white lead obtained as aforesaid, by what we call mashing it, as hereinbefore described." 3. For a Washing Machine and Clothes Press; Jonathan Read, city of New York, April 10. It seems that there was novelty enough found in this machine to justify the grant of a patent; the whole affair, however, is obscurely described, and very imperfectly represented in the drawings; and after a sufficient examination of the whole matter, we do not think the time and space would be profitably employed in endeavouring to make its structure and operation known. The claim if given, would afford no information, excepting that a certain shaft, handles, wheels, straps and treadles, are to be used. 4. For an improved Garden Cultivator; John Bush Smith, Princess Ann County, Virginia, April 10. This machine is furnished with teeth, in the manner of other cultivators; its frame is to be supported on two wheels which may be varied in their distance apart by being made to slide on their axle, for the purpose of marking the ground of different widths. It has two handles by which it may be guided, and at its fore part a strip rises vertically, which is furnished with a slot, to enable the person managing the machine to take proper sight. The "claims made, are to the mode of directing the course of the machine by means of the sighting staff, and of adjusting the machine for different widths by shifting the wheels on the axle, as described." The improvements thus claimed appear to be of doubtful originality, as it is no new thing to fix a rod or stick upright in front of an agricultural implement to sight by; we have seen this done many years since, but whether it is a common device we do not know. The shifting of the wheels upon the axle to mark the widths of rows for planting is used in Rockwell's machine, patented on the 12th of March, and described in the last number of this Journal; we believe that this also was no new device. 5. For Preventing Injury from the Explosion of Steam Boilers; Philip C. Friese, city of Baltimore, April 10. The nature of this invention will be clearly understood by an examination of the claims, which are to "the application to steam boilers of a jacket, possessing in its construction the following three peculiarities. "First. This jacket must envelope the steam boiler entirely, leaving throughout a certain intervening space between the jacket and the boiler. "Second. This jacket must have a convenient number of holes in it; each hole to be fitted with pipes bent to whatever direction it may, in each case, be considered most harmless to lead the steam in the event of an explosion of the boiler. "Third. This jacket must be able to resist, on every square inch of its inner surface, a pressure somewhat greater than the maximum that can be withstood on every square inch of the boiler." This is a plan that has been often thought of, and often proposed, but we do not recollect that it has ever before been made the subject of a patent. The practical, if not theoretical, objections to it are such as will not admit of |