228 SCIENCE PROGRESS. 



the market, or how he could produce something- which 

 would come up to the particular standard fixed for some 

 special work. 



It is most desirable too that there should be a few 

 machines in every country capable of dealing with full-sized 

 members of structures, such as built up struts, tiebars, etc., 

 this has been too much neglected in Great Britain ; in re- 

 gard to full-sized struts we are in need of much more de- 

 tailed experiments before anything can be done to put 

 the empirical formulae now in use on a more satisfactory 

 footing. In fact, as a rule, compressive tests to be of real 

 value must be made on the column or strut of the full size, 

 or at any rate as near to it as possible, since it is almost 

 impossible to deduce very satisfactory conclusions from the 

 results of the tests of mere specimens. 



Space does not permit me to deal with the equally 

 important question of temperature effects on the resist- 

 ance of iron and steel to stress, especially the effect of 

 long-continued alternations of temperature and stress. 

 Much good work has been done by Mr. Andrews and 

 others, but much still needs to be done if we are to de- 

 termine accurately the Physical Laws governing these 

 facts. 



T. Hudson Beare. 



