are formed. a 6, a circular spring, for compressing a 1 to the face of the slide-valve in Fig. 5, so as to render them perfectly steam and air tight; which perfection they will naturally acquire by constantly rubbing upon each other. a 7, a section of a box inclosing a 1, where the depth of the cell is shewn, and its connection with the face at the bottom of the box, the lid of which is not necessary but as a finishing to the valve-box. Figs. 6, 7, 8, and 9, shew four varieties of the slide-valve for working double and single powers. a 2, a 3, a 4, and a 5, contain the cells for conducting to the different apertures or steam-ways. a 8, the form of a lever or tappet for moving the slide-valves. a 9 and a 10, springs, with rollers, for pressing to the straight, or in part circular valves. Any farther description is unnecessary, as the drawings will convey to any one the principles of these inventions. Note. My new invention in this case consists in the application of one slide-valve, so contrived as to answer the purpose of the four valves, commonly used in double engines, or the two in single ones, and may be applied to engines of other constructions. Fig. 10, an enlarged view of the double conical centre and steel socket. a 11, the double-coned steel centre, screwed at both ends, one screw to fasten in the plane wheel F, represented in Figs. 1 and 2, where it acts as a crank for turning round the shaft G, the other end is screwed to receive a hollow cone, as represented. a 13, a nut, with two small screws, to prevent it from unscrewing. a 12, a section of the steel socket. a 14, plan of ditto. a 15, a square nut for the end of the steel conical pin. The invention and application of the conical pin to the wheel D, and connecting all the parts to the cistern, a frame of plates, as above described, constitutes the principle of this part of my invention. Note. The doubleVOL. II. SECOND SERIES. A a conical conical pin may be applied to engines of other descriptions. Figs. 11 and 12, elevation and ground-plan of the above inventions and arrangements extended to two cylinders, forming a double engine, and may be used for the purpose of turning machinery, drawing coals or other minerals from mines. The parts marked with the same letters in this engine are the same as in the preceding one, with the addition of the two wheels marked b, b, for turning the fly-wheel H. X, X, X, are dotted lines, shewing the method of turning an upright shaft with an horizontal fly-wheel. cc, a hollow cylinder, with the sliding-drum upon it dd, around which two ropes are wrapped, to which two baskets or curves are suspended in the pit ff. ee, a screw, that goes into the hollow part of the cylinder cc, and is attached to the drum d d by means of a groove in the cylinder cc: when the flywheel H is turned round by the engine, the screw ce draws the sliding-drum d d along the cylinder alternately, and causes the ropes to be coiled on and off the drum dd, and prevents the coils frem rubbing against, or wearing each other by lateral friction. One revolution of the screw must slide the drum rather more than the diameter of the rope. This method of the drum may be applied to beam-engines, or any other power for drawing coals, minerals, &c. My invention in this case consists in causing the drum to slide backwards and forwards, which prevents the destruction of the rope. In witness whereof, &c. Specification Specification of the Patent granted to BENJAMIN DOUGLAS PERKINS, of Leicester-square, London, Master of Arts ; for the Art of relieving and curing a variety of Aches, Pains, and Diseases in the Animal Body, by drawing over the Parts affected, or those contiguous thereto, in certain Directions, various pointed Metals, and compounds of Metals, which, from the Affinity they have with the offending Matter, or froin some other Cause, extract or draw out the same, and thus cure the Patients Dated March 10, 1798. To all to whom these presents shall come; &c. NOW KNOW YE, that in compliance with the said proviso, I the said Benjamin Douglas Perkins do hereby declare, that the said discovery is described as follows; that is to say: This invention or discovery consists in applying the influence of metals as a remedy in many diseases of the human body: The metallic substances which I employ for this purpose are those which produce that action on the nerves and muscles of animals, known by the term Galvanism. Among the metals that may be thus characterised, I have found none more eminently efficacious in removing diseases than the combinations of copper, zinc, and a small proportion of gold; a precise quantity of each not necessary: also iron, united to a very small proportion of silver and platina; an exact proportion of these also not necessary. These are constructed with points, and of such dimensions as convenience shall dictate. They may either be formed with one point, or pointed at each end, or with two or more points. The point of the instrument thus formed I apply to those parts of the body which are affected with diseases, and draw them off on the skin, to a considerable distance from the complaint, and usually towards the extremities. The diseases most readily cured by this metallic influence are rheumatism, gout, pleurisy, inflammations, spasmodic affections, and most kinds of topical complaints. All parts of the body on which the metals are to be used, as well as the metals themselves, should be perfectly free from oily and greasy applications. The relief from this metallic application may usually be expected in the course of from fifteen to twenty minutes; but in obstinate chronic diseases their use should be continued a much longer time, and repeated two or three times in the day for several weeks. In witness whereof, &c. On the Utility of Prussiate of Copper as a Pigment. By CHARLES HATCHETT, Esq. F. R. S. From the JOURNALS of the ROYAL INSTITUTION of GREAT BRITAIN. THE accidental discovery made by Diesbach of the pigment called Berlin or Prussian blue, about the year 1710, and which afterwards was published by Woodward in the Philosophical Transactions for 1724, was soon adopted by artists and manufacturers, so that in a short time the great utility of this colour was completely established; it is therefore remarkable, that but little attention has been subsequently paid to the colorific properties of the other metallic prussiates. The experiments made by Mr. Brown, with the prussic lixivium on various metallic solutions, do not merit particular attention, as the results evidently show that a very large portion of the alkali remained unsaturated with prussic acid, and thus the effects appeared different when the lixivium was prepared with blood or with muscle *. Bergman has however more accurately examined the properties of metallic precipitates (Opuscula. Tom. 2, p. 385), and especially notices the various colours of the prussiates; but neither he, nor any other chemist, as far as I am acquainted, has pointed out to artists the utility of prussiate of copper as a pigment. During some late experiments, I was much struck with the beauty of this precipitate, and was therefore induced to make several trials of it as a paint; the results exceeded my most san guine expectations. I afterwards prepared a large quantity, which, at my request, several gentlemen (particularly B. West, Esq. P. R. A. John Trumbull, Esq. and Sir H. C. Englefield) were so obliging to try in oil, and in water, and I have had the satisfaction to learn, that in beauty and intensity it surpasses every brown paint now in use, with the additional advantage, that, by reason of its purple tint, it forms, with white, various shades of bloom or lilac colour, which do not appear liable to fade like those which are formed by means of lake. The prussiates obtained from acetite, sulphate, nitrate, and muriate of copper, are all very beautiful, but the finest and deepest colour is afforded by the muriate. I have found also that prussiate of lime can be better depended upon for this purpose than prussiate of potash. The best mode therefore of forming this pigment, is to take green muriate of copper, diluted with about ten parts of distilled or rain water, and to pour in prussiate of lime until the whole is precipitated; the prussiate of copper is then to be well washed with cold water on the filter, and to be dried without heat. * Phil. Traps. 1724, p. 17, . Description |