1841.] 



THE CIVIL ENGINEER AND ARCHITECTS JOURNAL. 



429 



that some additional expense has been incurred in sinking the foundation of 

 the cross to a greater depth than was at tirst thought might he sufficient, in 

 order to ohtain a firmer basis, as well as in providing a more durable descrip- 

 tion of material for the foundation, according to a provision in the contract, 

 as what was to be obtained in this neighbourhood was not deemed sufficiently 

 good by the architect. — Oxford Herald. 



NEW INVENTIONS AND IMPROVEMENTS. 



CALOTYPE. 



Abstract of the specification of a patent gi-anled to WilUam Henry Fox 

 Talbot. Esq., of LilcocU Abbey, Wilts, for improvements in obtaining pictures 

 or representations of objects.— Enrolment Office, Aug\ist 8, 1841. — The best 

 and smoothest writing paper is washed on one side with a camel hair brush 

 dipped in a solution of 100 grains of crystalhsed nitrate of silver in six ounces 

 of distilled water. The siile being marked, to know it again, the paper is 

 dried before a distant fire, or in the dark, after which it is dipped f(ir a minute 

 or two in a solution of 500 grains of iodide of potassium in a pint of water ; 

 the paper is then dipped in water and dried. It is now called iodised paper, 

 and kept in a portfolio for use. Immediately Ijefore using, this iodised paper 

 is washed on the marked side with the folbiwing mixture :— 100 grains of 

 nitrate of silver are dissolved in two ounces of distilled water, to whicli solu- 

 tion one-fourth of ils volume of acetic acid is added. A saturated solution of 

 crystallised gallic acid, ur the tincture of galls, is mixed with the foregoing 

 in equal volumes, forming gallo-nitrate of silver. After being washed with 

 this mixture, the paper is dipped into water, it is then dried lightly with 



blotting paper, and finished by a distant fire. These operations should be 

 performed by candle-light. This paper, which the inventor calls •' Calotype 

 Paper," is used as follows :— A sheet of the paper is placed in a camera ob 



scura. so as to receive the image formed in the focus of the lens. If the ob- 

 ject is very bright, or the paper is exposed a sufficient time, a sensible image 

 will appear on the paper when removed from the camera obscura. But when 

 the object is "invisible or dimly seen," it is brought out in the following 

 manner :— The paper is washed over with gallo-nitrate of silver, and held be- 

 fore a gentle fire until the picture is sufficiently distinct, which is then fixed 

 in the following manner:— The paper is first dipped into water and partly 

 dried with blotting paper, after which it is washed with a solution of 100 

 grains of bromide ot potassium in eight or ten ounces of water; after which 

 the picture is again washed with water and dr:ed. In the picture thus ob- 

 tained, the lights and shades are reversed, but another being taken from it 

 restores Iheir natural position. For this purpose a second sheet of calotype 

 paper— or the patentee prefers using common photographic paper — is jilaced 

 in contact with the picture, a board placed beneath and a sheet of glass above 

 them, pressed into close contact by screws. On placing them in the sunshine 

 for a short time, a picture with the lights and shadows in their natural posi- 

 tion is produced on the second paper, which is to be fixed as before directed. 

 After frequent copying in this manner, a calotype picture sometimes becomes 

 faint, to prevent which, it is to be washed by candle-light with the gallo- 

 nitrate of silver. A second improvement consists in a mode of obtaining posi- 

 tive calotvpe pictures, i. r., with the lights and shades in their natural posi- 

 tion, by a single operation. For this purpose a sheet of calotyne paper is 

 exposed to the daylight until its surface is slightly browned ; it is tnen dipped 

 into the solution of iodide of potassium, by which the browning is apparently 

 removed. On being taken out of this solution, the paper is dipped in water 

 and slightly dried ; it is then placed in the camera obscura and pointed at an 

 object for five or ten minutes. The paper is then removed, washed with 

 gallo-nitrate of silver, and warmed, when a positive image will be produced. 

 A third improvement con.sists in producing photogenic images on copper; a 

 plate of polished copper is exposed to the vapour of iodine, or bromine, or the 

 two combined, or eitlier of them combined with chlorine ; or the copper is 

 dipped into a solution of some of these substances in alcohol, ether, &c. On 

 this copper a photogenic image is formed in the usual manner, and exposed 

 to the vapour of sulphuietted hydrogen, when a dift'erent colour is produced 

 on those parts of the copper which have been acted upon by the light to that 

 which appears on the parts not so exposed ; consequently, a permanent 

 coloured photogenic image is obtained, which is not injured by further ex- 

 posure to light. A fourth improvement is as follows ; — A thin coating of 

 silver is given to a plate of steel or other suitable metal, which is made sensi- 

 tive to I'ght in the usual way; the plate is then placed horizontally and 

 covered with a solution of acetate of lead, through wuich a galvanic current 

 being m de to pass a coloured film is precipitated on the picture. A fifth 

 improvement consists in a method of obtaining very thin surfaces of silver 

 for photographic processes. A very thin plate of copper is first precipitated 

 on a polished plate of metal by the electrotype process, and a sheet of card 

 is cemented to the back of the layer ; w hen dry, the card and copper are re- 

 moveil. and the copper silvered by immersion in a suiiable solution of that 

 metal. A sixth and last improvement is in transfetring photogenic pictures 

 from paper to metal. For this purpose, the surface is rendered sensitive to 

 light, and the picture placed upon it with a plate of glass in front, kei)t in 

 contact bv screws, and exposed to tlie sun's rays, when the required transfer 

 is eftected ; which is to be afterwards fixed, and otherwise treated according 

 to the effect required. — Mech. Mag. 



RAILWAY SIGNALS. 

 Abstract of a patent granted to Charles Hood, of Earl Street, Blackfriars, 

 for improvements in signals. Enrolment Office. August 1, 1841. — A suitable 

 receiver is filled with air condensed to about 45 lb. per square inch, by means 

 of a condensing syringe; this receiver is provided with a tube to which a 

 whistle is attached, similar to the steam whistle of locomotive engines, but 

 rather smaller. A stop-cock is placed upon the tube, between the whistle 



and the receiver, on turning of which the condensed air passes through, and 

 sounds the whistle. This contrivance enables the guard of a railway train 

 to give a signal to the engine-driver, in case of accident of any kind. It is 

 also applicable to steam boats, or to railway stations, for giving signals at 

 night, or in foggy weather. A second signal apparatus consists of four 

 wedge-shaped leaves or panels, which are centred at their pointed ends, de- 

 scribing an arc of 4.5", and spreading out like a fan. These leaves are at- 

 tached to each other in such a manner, that on pulling a cord, the lowest 

 leaf is drawn up behind the second, the second leaf behind the third, and all 

 three behind the fourth ; lastly, the four are drawn up into a case, by which 

 they are concealed. Each leaf is painted a different colour, indicating some 

 arbitrary sign. The raising or lowering of these fan-like leaves niny be done 

 by hand, or by means of machinery, tor night signals, each leaf has a pane 

 of glass let into it. on which figures. &C., may be painted, to indicate fixed 

 intervals of time, when worked by clock machinery. On an engine-driver 

 approaching one of these signal stations, the colour or number of the leaf 

 that is visible will convey the intelligence desired — to stop, to proceed cau- 

 tiously, or any other signal. If no leaf is visible, no signal is to be commu- 

 nicated, and he will fearlessly continue his progress. The claim is — 1. To 

 the mode of giving signals by applying condensed air in apparatus, in com- 

 Ijination with whistles. 2. I'o the mode of giving telegraphic signals on 

 railways, by means of moveable leaves or panels, worked either by hand or 

 by machinery, or by both means conjointly, and combining therewith clock 

 movements, or other similar machinery, for producing a gradual and ascer- 

 tained velocity of motion in the leaves or panels of the telegraph, and for the 

 continuous sounding of an alarm bell, as described. — Ibid. 



RAILWAY TURN TABLE. 



Abstract of a patent granted to Elisha Oldham, of Cricklade, Wilts, rail- 

 road contractor, for certain improvements in ihe construction of turning- 

 tables to be used on railways. Petty Bag Office. August 8. 1841 .—The upper 

 platform of the table is composed of a strong iron framing, filled in with 

 wood, and supported at ils centre upon an upright pin or pivot, lubricated 

 by means of an oil-chamber immediately over it. At the extreme edge, or at 

 a point nearer to the centre, the platform is supported upon eight iron anti- 

 friction rollers, mounted in bearings upon a stationary cast iron framing. 

 The whole weight-of the carriage, S;c.. rests entirely upon the centre pin, 

 when the platlorm is properly balanced; but if the weight is unequally 

 placed, one side of the platform will be sustained by the anti-friction rollers. 

 The claim is to the arrangement of parts herein described, as applied to the 

 ccnstruction of turn-tables ; or any other arrangement in which the moveable 

 platfoi-m is supported on a pin or pivot at its centre, and assisted by station- 

 ary anti-friction rollers at its sides, in the manner described.— ii/rf. 



DREDGING MACHINE. 



Abstract of an American patent granted for improvements in the Dredging 

 Machine, for deepening Harbours, Rivers, Canals, &c., to William Easby, 

 City of Washington, D C. August 25, 1841. 



This machine is intended to be worked by horses, that travel on a circular 

 platform, built on the deck of a large scow. The whole machine is made nar- 

 row enough to pass through a can.al lock, and in order to make the platform, 

 on which the horses travel, of sufficient size, a segment of the circle, called a 

 wing, is hinged on each side to the scow, so that in passing through a canal 

 lock, or any other narrow place, the wings may be turned up. The scoop is 

 to be worked by two barrels, or drums, placed one at the top, and the other 

 at the bottom, of a vertical shaft, in the middle of the platform— these drums 

 are, alternately, thrown in and out of gear by means of a vertical sliding 

 bolt, and a horizontal lever, worked by the attendant. The chain that draws 

 up the scoop passes around a roller at the end of the machine, and thence 

 around the barrel at the top of the shaft, and that which draws it down and 

 back, pisses under the platform, and winds on the lower barrel. 



The scoop is attached by one of its sides to two long guide poles, that 

 slide in loops made in twocolliirs, turning loosely on the ends of a horizontal 

 windlass, which forms the axis around which the scoop swings, when drawn 

 up or let down. In letting down the scoop, the chain which is attached to 

 its bottom, is drawn in by throw ing the lower barrel into gear ; this causes 

 the guide poles of the scoop to slide in the loops, which brings it near to the 

 windlass, and after it has passed a vertical line its gravity causes it to sink. 

 The lower barrel is then thrown out cf, and the upper into gear; by this the 

 scoop is drawn along the bottom, and filled, and then, with its load, is drawn 

 up out of water. The stuff raised is discharged from it into a scow, or other 

 receptacle, by pulling a rope, or chain, which disengages a spring catch, by 

 which the hinged bottom is fastened. The bottom is closed as the scoop 

 strikes the water, m the operation of being drawn down to be re-filled. The 

 distance to which the scoop descends below the windlass, around which it 

 works, is regulated by a chain, which winds around it, and is attached to a 

 brace connecting the two guide poles together, near the scoop. 



Claim— " What I claim as my invention, and desire to secure by letters 

 patent, consists in the arrangement of the barrels on the perpendicular shaft, 

 for winding and unwinding the main chains, in combination wuh the vertical 

 shding bolt aud lever, for throwing the barrels in. and out of gear, with the 

 shaft, by which the scoop, or bucket, is alternately raised, lowered, and 

 drawn back, whilst the animal, by which the mam shaft is turned, continues 

 to travel on the circular tracks w itbout interruption.' Also the combination 

 and arrangement of the parallel guide poles, chains, and windlass, for raising 

 the scoop, so as to draw it bick to its proper position, as described ; and this 

 I also claim in combination «ith the scoop and the apparatus lor^^" disen- 

 gaging the drop, or shutter, to discharge the load, as described. ' 1 also 

 claim "the arrangement uf the wings of the horse track, which can be raised, 

 and thereby reduce tlie width of the machine, .so that it may pass through a 

 canal lock, or any other narrow place, as described." — Franklin Journal. 



