1848. 



-THE CIVIL ENGINEER AND ARCHITECT'S JOURNAL. 



319 



The South- Furelniid Lighthouses. — These edifices are now completed, 

 and their appearance rcllccts credit on all parties concerDed in their erec- 

 tion. There are iwo — the one called the Upper, and the other the Lower 

 South.Forelaiid Li<;hlhouse. 'I he headland on which they stand is the 

 nearest point in England to the coast of France, the distance being barely 

 21 miles across the Channel. The upper lighlhouse consists of a massive 

 lower (externally uclagou, internally circular), the lanthorn of which is 

 about 375 feet above high-water mark, leaving a perpendicular height of 

 the clift' on which it is situated of about 290 feet. The lanthorn is con- 

 structed on a novel principle. It is furnished with 264 mirrors, which are 

 inclosed on the side opposite the sea by six lenses. These mirrors, casting 

 a niultitudinous reflection on each other, afford a stong and brilliant light, 

 being clearly visible on the opposite coast, throughout the Downs, Rams- 

 gate, and even Margate, and the greatest portion of the Isle of Thanet. 

 The lamp, which is in the centre of the lanthorn, consists of one large socket, 

 containing four burners ; and it supplies itself with oil by means of a kind 

 of dock-work machinery, which, while it pumps up the oil to the wick, 

 also returns the surplus quantity to the reservoir ; and in case of any 

 defects, or want of supply, by a small hydraulic balance, strikes a sharp 

 tinkling bell, as a warning to the keeper. The machinery is very simple, 

 andat the same time curious. The lanthorn consists ofa cupola, the roof and 

 sides of which are composed of neatly wrought-iion frames, apparently 

 light, but sutliciently strong to stand against the tempest. It is enclosed 

 by 48 oblong panes of plate-glass, from 2J to 4 feet long. Around the 

 cupola, on the exterior, is a balcony, rendered sate by a castellated para- 

 pel, from which, in clear weather, a splendid view is obtained. Passing 

 from the upper lighthouse, about a quarter of a mile easterly, is the lower 

 one, standing on the verge of the clitT. The tower is not so high as the 

 former, neither is it lighted on the same principle. Within the lanthorn 

 are suspended from copper branches 15 Argand lamps, each having a 

 burner of rather large dimensions with a concave reflector of the greatest 

 brilliancy, and about 20 inches in diameter. It appears that it is yet a 

 matter of doubt which system of lighting is preferable, but the Corpora- 

 tion of Trinity are giving each a fair trial. 



The " New Star," Steamboat. — Some experiments were tried on this ves-- 

 sel, on the river Thames, on the 27th ult.. preparatory to the building of a 

 new iron steamer. The trials were highly satisfactory, an average speed 

 being attained, after several trials at the mile distance at Northfleet, of 13 

 miles per hour in dead water. The engines and vessel were manufactured 

 by Messrs. Miller and Kivenhill. Tonnage, 265 ; oscillating engines of 68. 

 horse power ; diameter of cylinders, 34 inches ; length of stroke, 29 ; num- 

 ber of revolutions per minute, 48. 



Launch of a Steam-vessel in the Thames for Service in Scotland. — A 

 very haudsome-built iron boat was launched, on Saturday, the Itilh ult., 

 from the building-yard of Miller, RavenhiU, and Co., Orchard-wharf, 

 Blackwall. This is the third vessel turned out by the above tiim for the 

 Edinburgh and Northern Railway Company ; the two former vessels being 

 known as the Auld Reekie, and Thane of Fife. The new craft is expressly 

 adapted for the passage across the Frith of Forth, and will have a speed 

 superior to the I'ormer squadron. She was christened the E.rpress, and 

 will be furnished with a pair of oscillating engines of 120-horse power, 

 a pair of feathering wheels, tubular boilers, &c., which are now erecting 

 on board. Her length is 150 feet between her perpendiculars ; breadth, 

 148 feet at load line ; depth, 11 feet ; draught of water, 6 feet. 



Alleged Propulsion of a Vessel by Steam in the Year 1543. — RI. 

 Gonzales, director of the Royal Archives of Simaucas iu Spain, published 

 in 1826 an account of an invention by Biasco de Garay, a naval captain, 

 who, it is stated, exhibited in Spain, iu 1543. an engine, by which ships of 

 the largest size cuuld be propelled in a calm without the aid of oars or 

 sails. He made an experiment before commissioners, appointed for the 

 purpose of examining his invention at Barcelona, on the I7lh of June, 

 J 543 — the vessel used being a ship of 200 tons. Garay, we are informed, 

 wished to keep his mechanism a secret ; but it was observed to consist 

 partly of a large cauldron, or vessel of boiling water, and of two move- 

 able wheels, one on each side of the ship. The experiment succeeded so far, 

 that the vessel was propelled at the rate of two leagues in three hours ; 

 and the inventor was rewarded by receiving a sum of 200,000 maiavedis, 

 besides having his expenses defrayed from the public treasury. It is 

 added, that the invention would have been further encouraged had not 

 State expeditions of great consequence claimed the immediate attention of 

 the emperor. And it is important to tnention, that the authenticity of the 

 entire history of Garay's invention, as published by Gonzales, has been 

 called into question, and that do practical results of any utility followed. 

 Eraser's Magazine. 



Gutta Percha Boats. — At Seacombe, a No. 1 pilot boat, built of gutta 

 percha has been tested. It is 17j feet long, and though nearly filled with 

 water, and having four men on its gunwale, kept its buoyancy. It 

 weighs 1901b. and sustains a pressure of 15 cwt. It not only answers 

 the purpose of a pilot. boat, but is also convertible into a life-boat. This 

 substance must make an excellent life-boat ; and before we saw the above 

 account, we had thought of calling attention to the feasibility of this appli- 

 cation. The toughness, elasticity, and lightness of this material, for the 

 purpose of boat-building, is unquestionable. The price is one dollar per 

 pound, and 30 pounds must make a boat of a moderate size. The old 

 gutta percha can be sold at a reduced price. — iicienlific American. 



Indian Water/all. — Among the cliflTs of the Eastern Ghauts, about mid- 

 way between Bombay and Cape Comurin, rises the river Shirawati, which 

 falls into the Arabian Sea. The bed of the river is one-fourth of a mile 

 in direct breadth ; but the edge of the fall is elliptical, with a sweep of 

 half a mile. This body of water rushes at first, for SCO feet, over a slope 

 at an angle of 45", in a sheet of white foam, and is then precipitated to 

 the depth of 850 feet more into a black abyss, with a thundering noise. It 

 has, therefore, the depth of 1,150 feet! In the rainy season the river ap- 

 pears to be about 30 feet in depth at the fall ; in the dry season it is lower, 

 and is divided into three cascades of varied beauty and astonishing gran- 

 deur. Join our fall of Genesee to that of the St. Lawrence, and then 

 treble the two united, and we have the distance of the Shirawati cataract. 

 While we allow to Niagara a vast superiority in bulk, yet in respect to 

 distance of descent it is but a mountain rill compared with its Indian rival. 

 — Rochester Democrat. 



The American Lakes. — Professor Drake, of Cincinnati, has been making 

 some observations upon these inland seas, and gives the results to the 

 public. The chain of lakes extends over nearly eight and a half degrees 

 of longitude in length. The extent of their surface is estimated at 93,000 

 square miles ; and the area of country drained by them is computed at 

 400,000 square miles. Their relative sizes are as follows : — " Ontario, 

 5,300 square miles; Erie, 9,600 ; St. Clair, 300 ; Huron, 30,400; Supe- 

 rior, 22,000. The average depth of water in the diH'erent lakes is a ques- 

 tion upon which there is no certain information. Authorities differ. Dr. 

 Drake gives it as follows: — St. Clair, 20 feet ; Erie, 84 ; Ontario, 500 ; 

 Superior, 900 ; Huron, and Michigan, 1,000. In standard works. Lake 

 Erie is usually stated to have a depth of 120 feet. The depest soundings 

 have been made in Lake Huron. Ofl" Saginaw Bay, 1,800 feet of line 

 have been sent down without finding the bottom. The altitude of these lakes 

 varies step by step from Ontario to Superior. Lake Ontario is 232 feet 

 above the tide-water of the St. Lawrence. Erie is 333 feet above Ontario, 

 and 565 feet above the tide-water at Albany. St. Clair is 6 feet higher 

 than Erie; Huron and Michigan are 13 feet above St. Clair, and Superior 

 lies 44 feet above them. This shows the curious fact that while the sur- 

 face of Huron is 684 feet above the level of the ocean, its bottom, at 

 Saginaw Bay, is more than 1,100 below the same level. The waters of 

 these lakes, with the exception of Erie and St. Clair, are remarkable for 

 their transparency and delicious flavour. Of Lake Huron, Professor 

 Drake ascertained that the water at the surface, and 200 feet below the 

 same place, indicated precisely the same temperature, — namely, 56°. 

 His explanation of this fact is : the waters are so pure that the rays of 

 the sun meet with no solid matter in suspension to arrest and retain the 

 heat." 



New Cement. — The Buffalo Journal describes a valuable cement, which 

 was first discovered in Sharon, iMedina county, Ohio, and, after under- 

 going the most thorough test, has been pronounced of great value for 

 cementing roofs of buildings, steamboat decks, &c. The mine itself (says 

 the Cleveland Herald) is one of the most singulrtr depositories to be found. 

 It seems as if poured into a large sand-stone basin, covering some four 

 acres, is found at the depih of 20 feet, presents an even level surface, is 

 about 5 feet thick, and when dug out is no harder than tallow, and is en- 

 tirely free from dirt and other impurities. An exposure of two weeks to 

 the air changes the cement to stone, so hard, that it is diflicult to grind. 

 In preparing it, the cement is first ground when green, and after it has 

 been hardened, it is ground again, and remains in a powdered state until 

 mixed with oil for use. When applied to roofs, it becomes hard and 

 durable as slate, and is a certain fire-proof, and is iu no way affected by the 

 weather. We have been shown a specimen of the cement that has been ou 

 wood nine months, which adheres closely, is as hard as the slates used in 

 schools, shows pencil marks equally as well, and has the grit of a fine 

 hone. The cost is small, being 3 dollars per cwt., which, with the same 

 amount of oil, is sufficient to cover 1,200 square feet. 



A Portrait of Mr. T. Cubiit, by Pickersgill, has been subscribed for by 

 the Builder's Society. 



Salt. — A spring of brine has just been " tapped," by Mr. B. Smith, at 

 Droitwich, Cheshire, at the depth of 217 feet — being a greater depth than 

 any before discovered ; the usual depth being 170 or 180 feet. 



On the Occurrence of Vanadium in the Refinery Slag of Staffordshire. — 

 Mr. Deck, in a communication to the Chemical Gazette, says — "Being 

 commissioned by an eminent English railway engineer, who has directed 

 much attention towards the qualities of iron employed in bridges, &c., to 

 examine some refinery slag, which, without any assignable reason, had 

 the property of imparting extraoidinary ductility to the iron with which 

 it was mixed, I have succeeded in discoiering a large quantity of vanadium, 

 existing as silicate of vanadic acid, combined with small portions of 

 molybdena, chrome, and the usual quantities of phosphoric acid and sili- 

 cates. The first metal being confined to few localities, has had its pro- 

 perties but little studied by English chemists, and has hitherto been fuuud 

 in no other slag than that from the Taberg mine in Sweden, the iron of 

 which is remarkable for its ductility ; aud no mention is made of it in Dr. 

 Percy's elaborate analyses of slags for the British Association. The quan- 

 tity of slag at my command operated upon was very small ; but the vana- 

 dium existed in a ranch larger proportion than in the Swedish slag, which 

 1 have since examined ; and it is, doubtless, the cause of the superior 

 ductility of both." 



