184 MEMOIR OF THE LATE PROF. E. HODGKINSON, F.R.S. 



dimensions of tubes. The experiments which were devised 

 and carried out by Mr. Hodgkinson with a view to answer 

 the above questions are recorded in the Report of the 

 E/Oyal Commissioners appointed to inquire into the appli- 

 cation of iron to railway structures. 



Mr. Hodgkinson^ by these experiments^ sought — 



1 . To ascertain how far the strain upon a square inch at 

 the top and bottom of the tube would be aifected by chang- 

 ing the thickness of the metal^ the other dimensions being 

 the same. 



2. To obtain the strength of similar tubes. 



3. To find the strength of tubes of various forms of sec- 

 tion in the middle, and to furnish means of judging of the 

 proper proportions of the metal in the bottom, top, and 

 sides of the tube. 



4. To ascertain the relative strength of uniform tubes to 

 bear a weight in all parts of their length ; and whether 

 tubes, tapering in thickness from the middle towards the 

 ends, according to theory, would be equally strong in every 

 part. 



5 . To obtain the resistance of the tubes, previously tried 

 vertically, to bear a side pressure, with an intention to 

 ascertain the efiect of the wind upon a tube. 



6. To ascertain the strength of small tubes of difierent 

 forms of section to resist best a force of compression applied 

 in the direction of their length. 



7. To ascertain the resistance of wrought-iron plates to 

 a crushing force in the direction of their length. 



8. To determine the strength of tubes to sustain impact, 

 with reference to riveting. 



9. To determine, by bodies let faU upon tubes, the pro- 

 bable effect, if any, of trains rushing rapidly upon tubular 

 bridges, to produce resilience, or springing up at the ends. 



10. To determine the transverse strength of tubes stif- 

 fened in the top with cast iron, joined with wrought 



