OF lAON BEAMS. 437 



many remarks which his extensive knowledge, 

 particularly practical, rendered valuable to me^n 



26. I felt desirous of making, on malleable 

 iron, experiments similar to those already given on 

 cast iron, and for this purpose a bar a(bout 6 feet 

 long was made. It was of the same form as 

 those used in cast iron, its section being uniform 

 throughout, and in the shape of a t, of which 

 the top was 5 inches broad, and f of an inch 

 thick, and the vertical part or leg 1 f inch deep, 

 and nearly J inch thick. In the experiments, 

 one end was fixed horizontally and firmly 

 wedged into an immoveable object, a large 

 stack of pig iron, and weights were hung at 3 feet 

 distance, where the deflections were taken. The 

 experiments were made nearly in the same 

 manner as those on cast iron; only here, we 

 did not subject the same part to both tension 

 and compression, but contiguous parts. Thus, 

 suppose the first experiment was to extend the 

 vertical rib, the next experiment would be to 

 compress it in a part very near to the former 

 place; the piece having been taken out of its 

 fastenings, rendered straight if necessary, and 

 fastened again, the other side upwards, by the 

 part which was most strained before. This 

 mode was used, turning and shifting the piece, 

 throughout its whole length ; and toward the 



