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hydrogen, from a chemical union of which it can be easily 

 formed. No success had attended any attempt to collect 

 both oxygen and hydrogen into one experiment, without 

 having been absorbed by any other substance. The process 

 introduced by Professor Grove was clearly elucidated by 

 diagrams, and consisted in the introduction of two platina 

 wires into the lower part of a glass tube, hermetically sealed 

 and filled with water, from which the atmospheric air had 

 been expelled by the process of boiling. The wire is then 

 heated in an immense degree by the galvanic current, and 

 the intense heat has the effect of decomposing the water, and 

 the gases ascending to the top in large bubbles are collected 

 at the other end of the tube. The decomposition was pro- 

 duced by the action of the galvanic fluid. The result was 

 precisely the same by the hydrogen blowpipe. Dr. Scoresby 

 said it was necessary that the water used should be distilled, 

 or the result would not be the same. The plan was somewhat 

 analogous to that which had been laid down by Dr. Priestley, 

 though not altogether so. The impression left on the mind 

 of the Association at the time that it was introduced was, 

 that the experiment was singular, conclusive, and interesting. 



Dr. Scoresby next introduced the subject of the tunnel 

 tube across the Menai Straits, which was proposed to be 450 

 feet in length. The question to be decided in this matter 

 was, whether a tube of iron could be made to bear itself 

 when suspended on two points, and also carry a railway 

 train. The success of the experiment seemed to depend on 

 this fact ; and, from the tests which had been made by Mr. 

 Eaton Hodgkinson, as to whether a tube or mass of iron, set 

 edgeways, or in any other form, stretching to a considerable 

 distance, would have the same relative power of support with 

 a smaller piece of iron, it had been ascertained that the frames 

 of iron were arithmetically proportional to their relative di- 

 mensions. Having thus tested the capabilities of the iron. 



