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THE CIVIL ENGINEER AND ARCHITECT'S JOURNAL. 



[January, 



and chain of equal strength. The general results are, that standing 

 rigging of wire-rope, of equal strength with the hempen-rope, one- 

 third of the size and half the weight', may he fitted at about two-thirds 

 of the cost. 



In the nautical statistics of Mr. Smith's paper it is stated, in re- 

 ference to the advantages of a reduced surface of rigging, that " the 

 standing rigging now fitted in her Majesty's navy, presents a surface 

 of upwards of S00,000 square feet, which is about equal to the surface 

 of the sails of twenty-four first-class frigates ;" and in reference to the 

 disadvantages of the absorption of moisture by the hempen-rope, that 

 "one fathom of hempen-rope, about three inches in circumference, 

 will absorb half a pound weight of water, and will contract one inch in 

 length. The standing and running rigging of a first-rate measures 

 about 30,000 fathoms, and will, consequently when wet, contract in 

 length, on an average, about 8S0 yards, or nearly half a mile, and will 

 absorb about seven tons of water, which, being principally carried 

 aloft, will materially affect her sailing," &c. 



Mr. Smith explained the construction of an apparatus termed a 

 " screw lanyard," which he substitutes for the ordinary lanyards and 

 dead-eyes of the shrouds, for the purpose of tightening the wire-rope 

 rigging. It consists of a piece of Russell's wrought-iron tubing, with 

 a screw at each end, working in right and left screw sockets. 



The ship's lightning conductor is described as a copper-wire rope, 

 securely fitted to the trucks and mast-head caps, and descending from 

 the top-gallant and top-masts down the rigging, and over the ship's 

 side, where it is inserted in a copper-plate, in contact with the 

 sheathing below the water-line, &c. 



On Wednesday, the 21st of December, Mr. Smith continued his 

 communication. He commenced by explaining the tenacity and elas- 

 ticity of various metals, and experimented by a testing machine on 

 wires of platina, gold, silver, copper, and iron. He first tried a piece 

 ofplatina wire, twelve inches in length, -^ inch iu diameter, and 

 weighing S dwts. a grs; this experiment, however, failed from an 

 accident. The gold wire, of the same length and size, (weight 5 dwts. 

 lOgrs.) broke at3S41bs.; silver, same size and length (weight 4 dwts. 

 14 grs.), broke at 2G0 lbs ; copper, (3 dwts. 12 grs.) broke at 180 lbs. ; 

 and iron, 3 dwts., at 310 lbs. A copper rod, one-fourth of an inch in 

 diameter, was then tested, which withstood a tenison of 2,000 lbs. ; 

 and an iron one, of the same diameter, did not break until a power was 

 applied equal to upwards of 3,000 lbs. A wire bridge, of 33 feet span, 

 was erected in the room, the construction of which Mr. Smith ex- 

 plained. The wire rope, forming its principal support, weighed 50 lbs.; 

 the angle-irons, 112 lbs.; and the other parts, including the braces, 

 5(i lbs. ; and 112 lbs. for the platform or footpath, composed of boards 

 — thus making the whole weight only three cwt., and which might be 

 completed by four men, in about three days, at a cost not exceeding 

 15/., and could, at anytime, be taken down or put up in half an hour. 

 These descriptions of bridges were described as very useful for 

 military purposes, and for throwing over deep cuttings in railways, 

 &c, Mr. Smith stated, that for general practical purposes the 

 cost might be taken at )/. per foot run, with a breadth of three feet. 

 Two smaller models of bridges, on different principles of construction, 

 were also shown. 



KEENE'S MARBLE CEMENT. 



At the Society of Arts a paper was lately read by Mr. White, " On 

 Ktent' s Marhle Cantnt." It is described as a combination of sulphate 

 of lime and alum. The gypsum undergoes the same preparation as for 

 plaster of Paris, being deprived of its water of crystallisation by baking. 

 It is then steeped in a saturated solution of alum, and this compound, 

 when recalcined and reduced to a powder, is in a fit state for use. The 

 cement has been extensively applied as a stucco, but the finer quali- 

 ties (when coloured by the simple process of fusing mineral colours 

 in the water with which the cement powder is finally mixed for work- 

 ing) being susceptible of a high degree of polish, produce beautiful 

 imitations of mosaic, and other inlaid marbles, scagliola, &c. The 

 cement is not adapted to hydraulic purposes, or for exposure to the 

 weather, but has been used as a stucco in the internal decorations of 

 Windsor and Buckingham Palaces. From its extreme hardness, it 

 has been found serviceable, when used for imbedding and setting the 

 tiles of tesselated pavements, &c, and has been adopted for this pur- 

 pose at the French Protestant Church, the new fire-proof chambers in 

 Shnrtet's-court, and the Reform Club Honse. In the course of the 

 discussion which followed, Mr. C. H. Smith and Mr. Lee adverted to 

 the extreme hardness of the cement as its principal recommendation, 

 when applied as stucco and for mouldings. 



[We have seen some of the imitations of mosaic and inlaid marbles 



referred to in the above paper; we can say, and truly, that they are 

 beautiful, and in point of polish superior to scagliola; we have also 

 seen some fine specimens of granite, imitations in plinths for halls, 

 chimney-pieces, columns, pilasters, &c. ; and we must not forget to 

 mention the imitation statuary mouldings, with polychrome ornaments, 

 after the Greek. For the purposes of interior ornament, we consider 

 this cement a great acquisition to the architect. We, therefore, 

 strongly recommend the profession to visit Messrs. White's works, 

 where may be seen various applications of the cement for decorative 

 architecture, particularly two table tops, containiug several imitations 

 of rare marble?.] 



THE SILLOMETER, DERIYOMETER, SUB-MARINE THERMOMETER, 

 AND STEAM-ENGINE INDICATOR, OF M. CLEMENT. 



At the request of a subscriber to give some information relative to M. 

 Clement's Nautical instruments, for which Government lately made a grant, 

 we make the following extracts from the Mechanics' Magazine : — 



1. The Sillometer is the title given to a substitute for the common log, 

 which has been recently invented by a M. Clement, of Rochfort, and is so 

 well thought of by the French Admiralty, that it has been ordered to be 

 forthwith supplied to the different, ships of the Royal Navy of France. It is 

 a most ingeniously constructed instrument, and promises to be of great 

 practical utility. To describe it as well as we can in words : — 



A hollow copper ball, against which the water acts, is attached to a 

 moveable plug of-the same metal, which slides in a copper tube that passes 

 through the centre of the vessel to the keel ; to this plug is attached a lever, 

 which, by means of a vertical rod, acts on a second lever placed on the deck 

 of the vessel, and communicatiug with a spring ; the tension of the spring; 

 constitutes an equilibrium with the pressure of the water on the ball, and 

 serves to measure the rate at which the ship is moving, by means of a hand, 

 the movements of which on a graduated dial, indicate, at every movement, 

 not only the speed of the ship, but also the distance ruu in any given time. 



2. The second invention is called a Derivometer ; it is an instrument to 

 ascertain a ship's leeway, and is moved by a paddle, that may be placed 

 under the keel at will, and is supported by a plug sliding in a tube like that 

 of the Sillometer, but turning with the paddle and the rod. The motion is 

 transmitted from the paddle aud rod to two semi-circular dials, one of which 

 indicates the leeway to larboard, the other to starboard. When at anchor, 

 the instrument will show clearly the direction of the currents. 



3. The third invention is a Sub-marine Thermometer. It appears from 

 the thermometrical observations of many scientific navigators, that in seas 

 of unfathomable depth, the water is not so cold as over banks, and that 

 over banks near the shore it is less cold than over those at a greater distance, 

 but colder than in the open sea. M. Clement's thermometer is kept con- 

 stantly under water at the same depth, and indicates the different tempera- 

 tures of the water by means of a dial placed on the deck of the vessel, and 

 always open to examination. The immediate action is communicated by 

 wheels, the working of which turns two hands upon the dial, the one 

 marking the single degrees, and the other the tens. The whole is enclosed 

 in a tube attached to the side of the vessel, and the helix of the apparatus 

 is at the lowest part of the tube, in immediate contact with the water, and 

 always at the same height. 



4. The fourth invention consists of an instrument which indicates con- 

 stantly the elasticity of the steam both in high and low-pressure engines, 

 and the level also of the water in the boilers. The instrument may also be 

 applied to the piston of an engine, so as to show the loss of power sustained 

 by the steam in its way to it. A tube, similar to the manometer, is affixed 

 to the instrument through which the steam ascends, and is introduced into a 

 copper or brass box placed on the deck of the vessel, and upon which a 

 graduated dial indicates, by means of a hand, to the officer of the watch, 

 the effects of the engine, without his having to send below to ascertain it. 



M. Clement has obtained patents for these different inventions both in 

 France and this country. 



The following experiments made by order of the Lords of the Admiralty 

 on board of the Lightning steamer, we extract from the Government report. 

 " Thursday, October 13, 1842. 

 " About one mile and a quarter below Gravesend commenced a trial be- 

 tween Massey's patent log and M. Clement's sillometer. After a run of two 

 hours and a half (being off' Sheerness) — 



Miles. 

 " Distance given by Massey's log . . . 15-^ 



" Distance given by sillometer . . .15 



" Distance from the Nore Light to Deal by sillometer 42 

 " Distance by tables .... 41$ 



" At 25 minutes past 4 o'clock, p.m., altered the course four points, 

 during which operation the sillometer showed a diminution of speed from 

 8 miles per hour to 7 miles. At 50 minutes past 8 o'clock p.m., off South 

 Foreland, commenced a trial between Massey's log and the sillometer. 



" On Friday morning took in Massey's log, and found the distance from 

 abreast the South Foreland to about 7 miles to the eastward of the Owers— 



