154 Wisconsin Academy of Sciences, Arts, and Letters. 



matter cannot be too severely criticised, and the time must and 

 will come, when such information will be accepted only from 

 scientific organizations, where the same will have been thor- 

 oughly discussed before passing to the public. 



In iron, the matter is not quite so bad. Iron being a valua- 

 ble material, and a saving in weight of importance, so that an 

 excess in any structure over and above that which was actu- 

 ally necessary, would be a very expensive as well as worse than 

 useless application. This simple fact brought about a number 

 of experiments by able and reliable men, some of whom made 

 a specialty of the subject and deduced formulae which are now 

 in general use. 



Some valuable and carefully calculated tables on the 

 strength of columns were published in 1860, by Mr, G. P, 

 Kandall, in the Architects and Mechanics' Journal, and by Mr. 

 Wm, Bryson, in the Journal of the Franklin Institute, Both 

 were calculated from the formulae of Prof, E, Hodgkinson. 

 Mr. Randall assumes one-third of the breaking weight as the 

 weight of perfect safety, and thereby makes no allowance for 

 a misfit; and since a pillar imperfectly set is less than one-third 

 the strength of one properly fitted, this fact should have been 

 taken into account, Mr, Bryson, on the other hand, adopted 

 one-tenth of the breaking weight as the weight of perfect safety, 

 and carefully computes the minimum quantity of metal which 

 will support the weight under the assumed conditions, and at 

 the same time he is on the safe side in case of imperfect work- 

 manship. 



Quite recently an article comes from England which is not 

 only at variance with previous data, but contrary to all ac- 

 cepted laws. The following is the article : 



" Strength of Iron Increased by Strain.— Some experiments 

 recently made in England to ascertain the effects of strain on wrought 

 iron, give results quite at variance with the supposed data of previous 

 experiments, and are therefore worthy of attention. It is usually sup- 

 posed that the eifect of strain is to diminish the strength of iron, but if 



