64 



REPORT — 1853. 



Judging, however, from practical experience and observation, I am inclined 

 to think that the strengths of the metals are not much deteriorated. My ex- 

 periments on the effects of temperature on cast iron* do not indicate much 

 loss of strength up to a temperature of 600°. Assuming therefore that 

 copper and wrought iron plates follow the same law, and taking into account 

 the rapid conducting powers of the former, we may reasonably conclude that 

 the resisting powers of the plates and stays of locomotive boilers are not 

 seriously affected by the increased temperature to which they are subject in 

 a regular course of working. This part of the subject is, however, entitled 

 to future consideration ; and I trust that some of our able and intelligent 

 superintendents will institute further inquiries into a question which involves 

 considerations of some importance to the public, as well as to the advancement 

 of our knowledge in practical science. 



Appendix. 



In order to test with accuracy the tensile power of the different descriptions 

 of stays used in locomotive boilers, and to effect a comparison between those 

 screwed into the plates and those both screwed and riveted, it was deemed 

 expedient to repeat Mr. Ramsbottora's experiments on a larger scale ; and 

 by extending the tests to copper stays as well as iron ones, it was consi- 

 dered that no doubt could exist as to the ultimate strength of those simply 

 screwed, the tensile powers of the stays themselves, and the relative difference 

 between those and the finished stays when screwed and riveted on both sides 

 of the fire-box. 



The large lever and requisite apparatus being at hand, the experiments 

 proceeded as follows : — 



Experiments to determine the Ultimate Strength of Iron and Copper Stays 

 generally used in uniting the flat surfaces of Locomotive Boilers. 



Experiment I. — Iron Stay, fths of an inch in dia- 

 meter, screwed into a copper plate fths of an 

 inch thick. 



* Vide the Transactions of the British Association for the Advancement of Science, 

 vol. vi. p. 406. 



