44 ANNUAL OF SCIENTIFIC DISCOVERY. 



on a length of 10 ins. to the extent of 1.30 in. ; and the laying on of 

 50,346 Ibs. produced an elongation of 2.00, with a breaking weight per 

 square inch of, in pounds, 58,628, and in tons, 26.173. The diameter 

 at the point of fracture, after this experiment, was 0.88 in. The 

 second experiment was on a bar similar to the preceding, but rolled 

 cold. Diameter, 1.00 in. ; area, 0.7854 square inch. With a weight 

 of 64,255 Ibs. laid on, it elongated rapidly, and the breaking weight 

 was per square inch, in pounds, 81,812, and in tons, 36.523. The third 

 experiment was also on a bar of iron rolled cold, with a diameter and 

 area similar to the foregoing. The elongation of a length of 10 ins. 

 was, in inches, 0.6, when a weight of 62,545 Ibs. was laid on. With 

 69,295 Ibs. laid on, the elongation was 0.79 in., and the breaking weight 

 per square inch 88,230 Ibs., in tons 39.388. The diameter after frac- 

 ture was 0.85. The fourth experiment was on a bar of similar iron to 

 the preceding, turned in a lathe. Diameter and area same as in the 

 two foregoing. With a weight laid on of 30,910 Ibs. the elongation 

 was 0.15, and 2.20' with a weight of 47,710 Ibs. Here the breaking 

 weight per square inch was, in pounds, 60,746, in tons, 27.119. The 

 diameter after fracture was 0.80. Thus it will be seen, that in an un- 

 touched or black bar the breaking weight was 50,346 Ibs.; per square 

 inch 58,628 Ibs., or 26.173 tons strength, the untouched bar being unity, 

 1.000. That the breaking weight of a bar rolled cold was 69,295 Ibs. ; 

 per square inch 88,230 Ibs., or 39.388 in tons strength, the untouched 

 bar being unity, 1.505. The breaking weight of a turned bar was 

 47,710 Ibs. ; the breaking weight per square inch 60,746 Ibs., or 27.119 

 in tons strength, the untouched bar being unity, 1.006. From this it 

 is evident that the effect of consolidation by the process of cold rollino- 

 is to increase the tensile powers of resistance from 26.17 tons per square 

 inch to 39.38 tons, being in the ratio of 1 : 1.5, one half increase of 

 strength gained by the new process of cold rolling. When, however, 

 the iron rolled cold has repassed through the fire, many of the pores 

 before consolidated must again be opened, there arising a consequent 

 diminution of the strength previously gained. Experiments made at 

 Woolwich on the metal of a monster wrought-iron gun showed a 

 strength of 50,624 Ibs. in the direction of the grain, but of only 43,339 

 Ibs. when strained across the grain." London Engineer. 



IRON IN BUILDINGS - USEFUL RULES. 



From a paper recently read before the Liverpool Architectural 

 Society, by Mr. Wm. Stubbs, we derive the following useful memo- 

 randa : 



The first point to be ascertained by an architect with a casting of 

 iron is to find out what it has to do. The practical man wants simple 

 tools. Science is always consistent with successful practice, therefore 

 simple rules are sufficient. The following for iron pipes of ordinary 

 sizes answers well, and it never has been published before. It is based 

 upon the fact that a 10-inch pipe one inch thick will stand the pres- 

 sure of 100 yards head of water. The coincidence of one inch of metal 

 to every 10-inch diameter and 100 yards pressure should be remem- 

 bered. For every inch in the diameter of pipe, increase or deduct 



