1847.1 



THE CIVIL ENGINEER AND ARCHITECTS JOURNAL. 



293 



The model to be used in the bath, either of gold, silver, or copper, 

 is to have soldered on the back a piece of copper wire, for a conduc- 

 tor ; and the model is to be well cleaned with plumbago and a brush, 

 and its back fixed in wood, leaving only the required surface exposed. 

 Take a piece of zinc, about five ounces, and fasten on a screw, then 

 attach the copper wire to the screw, and place the piece of zinc in 

 one of the tubes D, suspending at the same time the model through 

 tlie centre hole, E, of the plate B, into the bath ; when the plate is 

 taken out of the bath, and taken oflf the model, it will exhibit a bur- 

 nish polish or dead appearance, according to the preparation of the 

 model ; it will also be found to be good and pliable metal, bearing 

 to be made several times hot without injuring or destroying the copy 

 of the finest engine-turning or engraving. 



Preparation for Silvering. — First dissolve 700 drams of sulphate 

 of soda recently prepared in four parts of warm filtered water. Se- 

 condly, dissolve 25 drams of carbonate of soda (when for use with 

 electric currents, but when to act by simple immersion, 75 drams are 

 used) in a pint of warm filtered water. Thirdly, dissolve 31 drams of 

 moist carbonate of silver. When these solutions are cold, mix the 

 sulphate of soda and the carbonate of soda together, then add the 

 rarbonate of silver, and stir all well with a glass stick till the silver is 

 well incorporated. This preparation is to be used cold. 



Battery. — When electric currents are to be used with the above 

 pnrposes, it is preferred to employ the battery shown in fig. 2, which 

 is constructed as follows : a is a glass jar ; b, a tube of charcoal ; c, a 

 porous vessel ; and e, a tube of amalgamated zinc. In making small 

 articles of silver, or of gold as hereafter explained, such as watch- 

 oases, three such batteries connected together form a proper strength 

 for the purpose; but for larger articles, more such batteries must be 

 used. Into the vessel a, put nitric acid and water, mixed in equal 

 quantities ; the tube of charcoal, b, is introduced into such vessel, a, 

 and the porous vessel, c, is introduced into the tube, b, and the liquid 

 thould then nearly fill the vessel a. Into the vessel, c, put a mixture 

 of i oz. sulpl>uric acid, 1 oz. common salt, and two pints of water. 

 The copper bands, d, of the three or other number of batteries used 

 are to be connected together, and these metal connections are to be 

 made between the models which are introduced into the bath to 

 receive precipitations thereon; the copper straps, /, are to be con- 

 nected to each other, and the one from the last battery is to have a 

 piece of platinum wire soldered at its end, and this platinum wire is 

 to be dipped about half an inch into the liquor of the bath. 



P reparation for Gilding. — First dissolve 375 drams of pure phos- 

 phate of soda in 4^ pints of warm filtered water. Secondly, dissolve 

 50 drams of recently-prepared sulphate of soda in half pint of warm 

 filtered w.iter. Thirdly, dissolve 7 drams of perfectly dry chloride of 

 gold in half pint of warm filtered water. Take the solution of gold 

 and mix it with the solution of phosphate of soda, then add the sul- 

 phate of soda. Care must be taken that they are well mixed. This 

 preparation is to be used warm, but not boiling. Tbis bath is to be 

 used with electric currents, preferring to use tor this purpose the bat- 

 tery above described for silvering. 



Preparation for Gilding by Immersion, — First dissolve 700 drams 

 of pure pyrophosphate of potash in five pints of warm filtered water; 

 if this solution is not clear, filter it and let it remain till it is cold. 

 Secondly, dissolve 7 drams of dry chloride of gold in half pint of 

 water, then pour this gently into the pyrophosphate of potass, taking 

 care to stir it well. This preparation to be used warm. This bath is 

 to be used in like manner to what has heretofore been done when 

 gilding by simple immersion, without the aid of electric currents. 



To prepare an electrotype model plate for gilding or silvering, 

 after it has been in the hands of the workman, first, put it in the es- 

 sence of turpentine for i hour, then Wash and brush it well, after 

 which put it in nitric acid diluted with water (i oz. of nitric acid of 

 commerce with two pints of water), to take away the oxide; then 

 place it ill cold water, and again brush it with rouge to give bril- 

 liancy ; place it next in fresh-made human urine lor eight or ten 

 minutes, and then again in cold water ; the plate is now fit for gilding 

 or silvering by the bath above described. By this process a coating 

 of gold or silver will be obtained, which when taken from the bath 

 will only require to be brushed with spirits of wine and rouge, and in 

 less than half-a-minute it will be as brilliant as when taken from the 

 model. It is not necessary to use the scratch-brush, or to burnish any 

 part of the plate, which is always required after other modes of gild- 

 ing and silvering, and which always injures fine engine-turning and 

 engraving. 



ROTARY ENGINES. 



William Breynton, of the Inner Temple, in the city of London, 

 gentleman, for "certain improvements in rotatory steam-engines." — 

 Granted January 21 ; Enrolled July 21, 1847. [Reported in the Patent 



Journal.'] 



This specification is accompanied by a diagram (see the figure) 

 illustrative of the principle on which the rotatory engines are to be 

 constructed. A, B, C, D, is an ellipse, described with foci, E, and F, 

 half the major axis, or transverse diameter of which, is represented by 

 O, B, =: a, (a known nuniber= 1-5904) whilst half the minor axis or 

 conjugate diameter is represented by O, A, = 6, (another known num- 



ber=r 1-5) ; the focal distance is represented by O, E, and 0. F, = c, 

 (= -524). A, K, H, L, is a circle described with centre G, and radius, 

 G, A, which radius, = d, (= iof O, A,). X, Y, represents a circle 

 described with centre, G, and radius G, O,^ e, (='5) ; the remaining 

 parts will hereafter be more particularly described and alluded to; 

 bat it may be as well to observe that N, S, represents a piston passing 

 freely through the centre of the circle, A, K, H, L, (and having a slid- 

 ing motion in the direction of its length,) whilst m, n, is intended to 

 show the thickness thereof. In an engine constructed upon the prin- 

 ciple above shown, A, B, C, D, then would represent the outer iron 

 case as it would appear in vertical section, and which case, therefore, 

 would bj of an elliptical form, although employed for a similar pur- 

 pose to that part of an ordinary steam-engine known by the name of 

 the cylinder ; below, or at C, would be the foundation-plate, upon 

 which the said elliptical case would have to be fixed. A, K, H, L, 

 marks the plice that would have to be occupied by a hollow cylindri- 

 cal shaft or piston-rod (of considerable diameter), and which is placed 

 at such a distance, it will be observed, from and above the centre of 

 the elliptical case, A, B, C, D, as that the circumference of the said 

 shaft or piston-rod shall come in contact with the inner surface of the 

 elliptical case at the point. A, and at which would be the slide-valve 

 so arranged, that the steam might be introduced into the elliptical 

 case, say at or near to such point. A, or at;:;, when by acting upon the 

 sliding-piston, N, S, it must, thereby, impart a rotatory motion to the 

 shaft, A,K,H,L,and the steam ultimately would be discharged through 

 an aperture or eduction-passage, somewhere near also to the point, A, 

 or at/; or the steam might be introduced and allowed to pass off 

 through the ends of the case, if found advisable. For reversing the 

 engine, or causing the piston and shaft to move in a contrary direction, 

 it would only be necessary to make the eduction-pipe available for 

 the passage of the steam out of the cylinder, by altering the position 

 of the cock or slide-valve, and in the usual way, the shaft, A,K, H,L, 

 most pass through steam-tight stulBng boxes at each end of the case, 

 and revolve in bearings in the upright frame attached to the founda- 

 tion-plate. The sliding piston, N, S, will be rectangular, its breadth 

 being equal to the distance between the ends or side-plates of the 

 elliptical case, whatever that may be, and its length (as shown at 

 N, S,) equal, or nearly so, to the shorter diameter of the same. Tbis 

 piston must slide through a slot or aperture in the shaft or piston-rod, 

 so that whilst the rod moves in a circular direction, the sliding piston 

 moving with it and through it, performs an elliptical course by reason 

 of the pressure of its extremities against the inner surface of the case; 

 and the ends of the piston, as the patentee observes, should be kept 

 in close contact with such inner surface of the case by aid of metallic 

 packings and of springs, the elasticity of the latter, by exerting a con- 

 stant outward pressure against the former, serving to accomplish such 

 object. 



