18^2.] 



THE CIVIL ENGINEER AND ARCHITECT'S JOURNAL. 



243 



M. Dupasquier read a paper On the iise of iron as a tesl in Marsh's appa- 

 ratus/or the detection of arsenic. M. Dupasqiiier stated unequivocally, that 

 by>the use of a preparation of iron, such as had been resorted to at times by 

 cMbists intrusted with the task of testing the presence of arsenic, stains 

 apparently arsenical, but which are not so, may be produced. 



April 11. — A paper was read by M. Domeiko, On the siher minen in Chili, 

 and the mode of working them. " The mines extend from the north to the 

 south, parallel with the coast, to a distance of 1.^0 leagues fiom the environs 

 of St. Yago to the other side nf Copaipo. The silver mines of .Vcqueros, 

 which are the special subject of the paper communicated to the Academy, 

 ■were discovered in 1825 by a muleteer, whilst collecting wood on the moun- 

 tain. He found by chance sever.-!! small blocks of native silver, and, having 

 mentioned his discovery to hi> acquaintances, they proceeded to the spot, 

 and collected immediately silver to the value of 10,000 dollars. Soon after- 

 wards the vein itself was'discovertd, and its richness was foiiud to equal all 

 that had been anticipated. From that period up to 1840, the date of the 

 last returns, this vein has jlelded about 30,000 marcs of silver annually. 



A paper was read On the Dcytierreotype improvements of M. llisson. M- 

 Bisson, by a galvanic process, covers the plate with a slight coating of silver, 

 much more even and perfect than the surface of the ordinary silvered plate, 

 and the object was, consequently, represented with greater fidelity and bold- 

 ness. .Another improvement of M. Bisson's is. in giving, by tlie .action of 

 the galvanic pile, a slight gold tint to the drawing, nliich takes away its 

 unpleasant looking-glass appearance, and causes the oljjects to stand forth 

 almost as clearly and vigorously as in drawings produced by hand. 



Ajtril 18. — A paper was read by M. Regnault, On the dilaling powers of 

 gases, and on the i-elntire powers of air and mermrial thermometers. 



A specimen of a reddish sediment, deposited by a shower of rain at Am- 

 phissa, in Greece, on the night of the 24th ult., and forwarded by M. Bouros, 

 with a paper on the subject, was examined by the Academy. The last mail 

 from Smyrna brought an account of a similar fall of rain at about the same 

 time, due of the journals of that place, alluding to this phenomenon, states, 

 that the sediment resembled the sand of the desert, and supposes it to have 

 been taken up by a whirlwind, and, combining in the clouds with water, to 

 have been held in suspension until it had travelled to a distance of nearly 

 1,000 miles to Smyrna. The wind, adds the Smyrna Journal, was blowing 

 fresh from the southward at the time, bringing heavy clouds, accompanied 

 bv a peculiarly hazy atmosphere, observable only in long continued siroccos. 



May 3. — .\ paper was read from M. Reville, of Havre, On the use of cotton 

 sails for ships, as more economical than those made from tiax, and being 

 at the same time equally serviceable. Certificates from various persons who 

 have made use of cotton sails, and specimens of their old and new were laid 

 before the Academy. 



From Messrs. Hempeland Ilamann, On a new Compass, of their invention, 

 for meastiriny ellipses. The report of Col. Puissant and M. Sturm on this 

 invention, which was read to the .Academy, states it to be superior to any 

 instrument for the same purpose hitherto known ; consequently, the Academy 

 decided on expressing pubUcly its approbation of the invention. 



From M. Jobard, of Brussels, on some experiments which he proposes to 

 make, with a view of ascertaining the best means of prerenting the explosion 

 of steam boilers. The principal experiment proposed by M. Jobard is, such 

 a construction of the boiler as will permit, when the mixture of explosive 

 gases has been formed, the introduction of a stream of atmospheric air, so as 

 to render them inexplosive. 



From M. de Castelnau, On some geological revolutions in the central parts 

 of North .Imerica. The period to which M. de Castelnau directs the atten- 

 tion of the Academy is that corresponding with the geological revolution to 

 which the bordering portions of Canada and the United States owe their 

 present configuration, viz. that which formed the great Lake of Canada, ex- 

 tending from east to west, with the exception of Lake Michigan, the direction 

 of which is from the north to the south, with a slight deviation towards the 

 west. At the south of the southern point of this lake, there extend toward 

 the Ohio on the one side, and the Mississippi on the other, vast prairies, 

 entirely formed of deep alluvial soil covering an old calcareous bed. Every 

 thing indicates, says M. de Castelnau, that this region was formerly the hasi]i 

 of a lake of much greater extent than those which now exist in this part of 

 the world, and, on approaching the Mississippi, the proofs of this pheno- 

 menon become more evident. He considers it certain, that at a remote 

 period there was some obstruction to the course of the Mississippi, which 

 produced a stagnation of its waters, and raised them to an elevation of 40 

 metres ; for wherever the rocks present an abrupt front towards the river, 

 they offer a series of parallel lines, inclining slightly towards the north. The 

 geological formation of the land in the vicinity of Lake Huron, presents the 

 character of a vast Silurian formation. According to M. de Castelnau, Lake 

 Superior formerly discharged itself into Lake Michigan, which had its termi- 

 nation in an immense basin, to which he gives the name of Lake Silurian, 

 and which probably discharged the excess of its contents into the Mexican 

 Sea ; but a revolution of nature checked the passage of the waters to the 

 extremity of Lake Michigan, and produced at Lake Silurian the rising ground 

 known as the Illinois, wliich must have been of greater extent than it is now, 

 asd it is not impossible, that with its progressive depression, the waters will 

 at some distant period resume their former course. 



Mag 9. — At a special meeting M. Cordier communicated various de- 

 tails relating to the horrible accident on the Versailles railroad, ex- 

 tracted from an official report addressed to the Minister of the In- 

 terior by Messrs. Combes and De Senarmont, the engineers of Mines, charged 

 with the inspection of rail-roads. In addition to the facts already known, 

 it states that the foremost locomotive was a small one, with four wheels, 

 and the other one of large dimensions with six wheels, made by Sharp and 

 Roberts. The boilers of both are at present without the slightest injury. 

 According to the testimony of the Commissary of Police of Meudon, one of 

 the carriages was altogether consumed in ten minutes. The report contains 

 the following summary as to the cause of the calamity. The accident ori- 

 ginated in a fatal concurrence of circumstances, which were all gross faults, 

 easy to have been foreseen, and still more easily to have been avoided. The 

 first cause of the accident was the employment of a locomotive with four 

 wheels. It is essential that every carriage intended for service on a railroad 

 should rest on six wheels .it least, in order that if one of the axles should 

 break, the carriage should rest on supporters, and continue its course. The 

 second fault consisted in the employment of two locomotives for a single 

 train. The consequences of this arrangement are self-evident. .\ third cir- 

 cumstance was, the precaution taken to lock the door of the wagons ; so that 

 in such a case as that which occurred, all escape was prevented, and the tra- 

 vellers were condemned to suffer all the consequences of the first accident. 

 Another cause which had much influence on the catastrophe, was the neglect 

 to isolate the train from the locomotive, so as to prevent the shock occa- 

 sioned by the sudden check to the speed with which they were proceeding. 

 It is worthy of remark, that if all those causes had not existed together, and 

 if only a single precaution had been taken, the accident would not have hap- 

 pened. If the first engine had been furnished with six wheels when its axle 

 broke, it would not have lost its equilibrium. If a second locomotive had 

 not been employed, the only consequence of the accident would have been 

 a shock ; and, even admitting that the two first causes of the accident existed, 

 had the doors of the wagons not been locked, a number of the passengers 

 might have escaped the flames ; and the interposition of the elastic system 

 would have saved the train even if no other precaution had been observed. 

 The Academy listened to the account in mournful silence. Several members 

 afterwards made remarks on the inconvenience of using locomotives with 

 four wheels ; M. Elie de Beaumont particulariy protested against immense 

 trains being drawn by several locomotives, the danger increasing in propor- 

 tion to the number of machines employed. The custom of locking up the 

 passengers was also much spokeij against. Towards the close of the sitting, 

 a rumour having spread in the Academy that Admiral Dumout d'Urville was 

 amongst the number of the dead, or at least that he had not been found 

 after the accident, it being certain that he had entered one of the foremost 

 wagons, yi. Arago proposed that two members should be appointed to make 

 inquiries respecting him ; and if they found him among the wounded, to tes- 

 tify to him all the interest that the Academy took in his fate. 



A report by M. Segnin, was read, of a series of experiments performed by 

 order of the .\cademy on the cuirass made of hemp, the invention of M. 

 Papadapoulo. The report states, that the balls of cavalry pistols, fired at a 

 distance of from three to five paces, only penetrate to a depth of about the 

 third of an inch ; consequently, the report is favourable to the inventor ; but 

 a discussion having arisen on some points not alluded to in the report, the 

 decision of the Academy, as to the value and importance of the invention, 

 stands over until the points under discussion shall have been treated upon 

 by the reporter. 



RIISCEI.I.AMEA. 



Tlic Monster Steam i'n/p.— This vessel, which is nearly ready to be launched, 

 is built by three or fonr spirited individuals on their own speculation in the 

 small toHn of Derry, Ireland, where a fe« mcnth.s previously it was never 

 supposed that a vessel of her magnitude would ever be built ; her dimensions 

 are 222 ft. in length between perpendiculars. 37 feet beam, and 2f; feet deep 

 in the hold, burthen 1750 tons, B.M., she is to be fully rigged as a 50 gun 

 frigate, the length of main mast to be flO ft. and 33 inches diameter, main 

 yard 79 It. and "22* ft. diam. in the slings, foremast 83 ft. and mizen mast 

 76 feet, she will be'ablc to spread 6,400 yards of canvas. There are three decks, 

 the upper one to be left entirely clear for action, and to be pierced lor 

 ■M guns, the windlass anri capstan gear will be placed "twixt decks. .'-Ihe is 

 to be propelled by .Smith's Archimedean Screw, which will be 12 ft. diam. 

 and M ft. pitch, but the length will be only 7 ft.: it is to make 88 revolutions 

 per minute, llie gearing consists of a cog wheel 20 ft. diam.. working into a 

 .smaller wheel of 5 ft. diam., upon who.se axis is the shaft of the screws. 

 The engine power consists of two cylinders (iS in. diam., 4 ft. 6 m. stroke, 

 and to make 22 strokes per minute, nominal power 306 horses ; there are to 

 be fcur .air pumps 11) in. diam. and 4 ft. 6 in. stroke, and 3 cylindrical boi ers. 

 The engines are to be placed close abalt the vessel, leaving the midships cjear 

 for passengers. 



A very beatdifu! stained glass window has recently been put up over the altar 

 of West Hackney church, 'the centre part of which is a copy o' >l»e celcbra'ed 

 altar-piece at Mrgdalen College, Oxford— Christ bearing the cross, very hnely 

 coloured, from the original picture ; and on either side stand out in bold 

 relief ihejfigures of St. Paul and St. Peter, after Uaphael. They stand lu 



