372 THE SCIENTIFIC PAPERS OF 



I quite believe is a step in the right direction. The other is an 

 experiment of construction which I had occasion to make, and 

 which, by Mr. Parker's request, I have put before the meeting. I 

 was asked to design a vessel that could resist the pressure of at 

 least 1,000 Ibs. per square inch, and with a capacity of not less 

 than 100 cubic feet. The mode in which such high pressure air- 

 vessels have been hitherto constructed has been in making them 

 multitubular, but in resorting to that construction you get many 

 joints and you have also a voluminous structure. It occurred to 

 me that a better result would be gained by rolling cylindrical 

 bands of metal from solid steel ingots cylinders of 1 foot in 

 depth and 44 inches in diameter. In rolling metal in this fashion 

 you get the whole strength of the metal in the right form for re- 

 sisting a bursting strain. The difficulty was to make joints between 

 the cylinders, and this was accomplished by turning in the face 

 of each a V groove of about \ inch deep, rings of copper wire of 

 f inch thickness are thereupon placed between groove and groove, 

 and the whole set of cylinders are screwed up and bolted together 

 by sixteen or twenty long bolts made of steel of great elasticity 

 containing about \ per cent, carbon, with a resisting power of 

 about 50 tons to the square inch on the ends of the vessel. 

 After screwing down these bolts hydraulic pressure was applied, 

 and the vessel stood 1,300 Ibs. to the square inch without a leak, 

 but at that point a great many joints began to weep. The bolts 

 were then drawn up |th of a turn, when the vessel was found to 

 be perfectly tight at the pressure of 1,300 Ibs., but the joints 

 began to weep' again at 1,400 pounds. We might have continued 

 the operation of drawing up and have reached a higher limit of 

 pressure, and seen whether all the parts of the vessel were not 

 strong enough to resist 2,000 Ibs. to the inch, but inasmuch as 

 the vessel in use was only to resist a pressure of 1,000 Ibs. to the 

 square inch, it was thought sufficient to tighten these bolts to the 

 limit of 1,400 Ibs., because we felt that if ever the pressure should 

 reach that point the bolts would yield owing to their elastic 

 property, and allow the fluid within to escape, thus avoiding the 

 risk of an explosion taking place. In that way vessels I believe 

 can be constructed which are perfectly safe and capable of resist- 

 ing a very high pressure. I may mention that in this form steel 

 will bear a pressure of 45 tons to the inch with perfect ease and 



