456 



Mr. J. B. Hannay. 



[May 27,. 



liquid was even worse to work with than the hydrocarbon, as on coming 

 into contact with the hot iron it burnt it away at once, and as the tube 

 was of great diameter it was extremely difficult to keep the lower part 

 cool. For welding it had to be arranged so that it was standing in a 

 tub of ice, and the top projecting through the bottom of the forge, 

 and heated until it was at a welding heat, with as little delay as 

 possible. When a tube was obtained welded up solid it was heated to 

 a dull red-heat for 14 hours, and allowed to cool ; on opening the tube 

 there was a very great out-rush of gas, and the carbon was to a certain 

 extent dissolved, and some minute portions of it very hard. Still, 

 under the microscope it presented little difference in appearance from 

 the wood charcoal employed, some of the features, however, being 

 obliterated, and it had a bright appearance. Another tube of the same 

 dimensions and contents was closed up in the same manner, but after 

 eight hours' heating it burst with a loud explosion. I had noticed that 

 a tube which had been once used and been partially carbonised would 

 not stand a second heating, and for this reason I had no belief in the 

 power of cast-iron or steel to withstand the great pressure at a red- 

 heat. Nevertheless, as many of my friends had urged upon me to try 

 these materials, I had a cast-iron tube made, 3f " x 24" x §" bore, a.nd 

 filled two-thirds of its volume with bone oil distillate and carbon, and 

 then welded up. We succeeded after a little trouble in making a good 

 weld, and the tube was then slowly raised to a dull red-heat in the 

 furnace. It had not been heated for more than an hour when it ex- 

 ploded with a great noise, and knocked down the back and one of the 

 ends of the furnace, leaving the whole structure a wreck. The tube 

 had broken into small fragments, and was quite unlike the malleable 

 iron tubes which generally tore up. Thinking that it was perhaps a 

 bad casting, I tried another, but it leaked all over, and emptied itself 

 before the temperature was nearly up. A third tube of the same 

 material burst like the first, but as I had built up the furnace with 

 large blast-furnace blocks, it w r as not blown down. Cast-iron being 

 inadmissible, experiments were then made with steel. I had several 

 tubes made of this material by the best firms in the kingdom — made 

 bv the three methods, Bessemer, Siemens, and the crucible method — 

 but they had the same faults as cast-iron, although to a less degree. 

 The difficulty in making a good weld in cast-iron and steel tubes makes 

 their employment in such experiments as these a matter of incon- 

 venience. Out of five tubes made of steel, some of which were made 

 of the very toughest material manufactured by Messrs. Cammell and 

 Co., only one held in the substance completely. Three burst in the 

 f arnace, and one had leaked by its porosity. The top of the furnace, 

 by the continued shocks of explosions, fell in at the bursting of the 

 last of the steel tubes. The continued strain on the nerves, watching 

 the temperature of the furnace, and in a state of tension in case of an 



