88 ^ ANNUAL OF SCIENTIFIC DISCOVERY. 



built up of many small pieces of lime from chalk; it is about Sf 

 inches in diameter and 16 inches long. It is supported by a clock 

 which, when in action, lifts it perpendicularly, at the rate of 1 

 inch per hour. Eight gas jets, conveying mixed ox} 7 gen and 

 Ivydrogen, are placed at equidistances around this lime, in a hori- 

 zontal plane. When the gases are lighted and directed against 

 the lime, they produce 8 places of intense ignition ; and as the 

 lime core is about 11.4 inches in circumference, the centres of 

 these 8 frames are about 1.4 inches apart. 



" The lamp practice in the lantern is very easy ; the jets are 

 easily and safely lighted and adjusted. The action then goes on 

 for hours together without change. The clock raises the lime; 

 draughts do not affect the light ; there is apparently no circum- 

 stance present which can cause derangement, and, as far as 

 appears by theory or practice, the lamp may be left until sunrise 

 untouched, provided gas be regularly supplied from below. The 

 lamp is easier of management than a common oil lamp. It is 

 easily replaced, in case of need, by the ordinary oil lamp ; and 

 that has been done in times varying from 7 minutes to 10 minutes 

 or more. 



** The. light produced is very white and beautiful in character, 

 far surpassing that of oil or gas flame in its intensity, but not 

 equal to the electric spark ; but then it is much larger in dimen- 

 sion. It is like the light of a planet, whereas the electric light is like 

 that of a star. It streams out from the lantern over the surround- 

 ing space in great abundance. 



" The good and constant condition of the lamp will depend 

 upon the sufficient and steady supply of the gases required. At 

 present these are oxygen and hydrogen. 



"The oxygen is made by the ignition of the native peroxide 

 of manganese, in iron retorts fixed in a furnace, heated to bright 

 redness by coke. 



"The oxygen, after being passed through a washer, is con- 

 ducted to a gas-holder capable of holding 600 cubic feet of gas ; 

 it is outside the building, appears to be steady in its action, and 

 fit for its peculiar service. The pipes conveying the gas are 1^ 

 inches in diameter outside the tower, and 1 inch in the tower. 

 No inconvenience has as yet been experienced, at Westminster 

 Bridge or elsewhere, from the action of cold on such exposed 

 pipes. There are cocks at the gas-holder, and also in the lantern, 

 governing the progress of the gas. The pressure upon it, when 

 the lamp is burning, is 6 inches of water. 



" The hydrogen gas is at present made by heating to redness 

 a mixture of equal weights of iron borings and crushed coke dust 

 in iron tubes placed in a special furnace, and then passing over it 

 a stream of steam. There are 3 tubes, which require only once 

 charging for the day ; and they, with the furnace, seem to do 

 their duty very well. The gas is passed through a washer, as in the 

 former case, and then on to a gasometer of the same size and 

 arrangement as that for the oxygen. A sufficient supply for the 

 night's consumption is produced in 3 hours. 



" There is an apparatus for the gone ration of hydrogen by the 



