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was made, was originally of the strongest and toughest kind, 

 and entirely fibrous. It had become granular and brittle by 

 being subjected to great vibration at a temperature very con- 

 siderably below that of boiling water. He was unable to 

 exhibit a sample of the identical billet from which this broken 

 pin was made, because Mr. William Lucas, who took it with 

 him to Manchester, had given it to Sir Henry De la Beche, 

 to be placed in the Museum of Economic Geology; but he 

 had provided himself with a small specimen of similar tough 

 iron for the purpose of comparison. The manufacture of the 

 pins was then explained. Puddle bars were made from the 

 best Shropshire and Staffordshire cold blast grey pig iron, 

 piled seven high, ball-furnaced, shingled, and rolled into a 

 billet, which was drawn down to the size required under a 

 small forge hammer. The pins were used to hold down the 

 brasses over the neck at the end of the long shaft which turns 

 the little mill, and this shaft, as it revolves nearly 300 times 

 per minute, experiences a violent vibration. When the mill 

 was in action, the temperature of the pins was not above 

 100° of Fahrenheit, and they were in no part nearer to the 

 point of friction than six inches. The cause of the pins not 

 having attained a greater degree of heat, was on account of 

 their distance from the nearest point of friction, and also 

 from the brasses being well supplied with oil and grease. 

 The pins had been in use for two or three months when they 

 broke, and their breaking caused the breaking of a wheel, 

 and also of the bed of the carriage at the end of the shaft. 

 Mr. Solly said frequent cases of this kind had occurred at 

 their iron works, at Tividale, in Staffordshire, particularly 

 with the pins on which the shears work ; the shears, being used 

 for cutting bars of iron cold, are subjected to constant small 

 shocks or jerks. He had lately had an opportunity of exam- 

 ining at the Railway Station, Derby, four broken axletrees, 

 all of which presented a crystalline appearance. One of the 



