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absent. By mechauical eng-ineers I was told, that the alloy for 

 boaiings must not ho heated further than uecessary for giving it 

 sufficient fluidity, then stirred and cast without delay in moulds 

 heated to the boiling point of water. 



In Babbits metal, heated till its surface becomes smooth and bright 

 the majority of the crystals is not liquified. Castings, made of such 

 metal, without previous stirring, consist of tin, with about 4 "/g of 

 copper and antimony, while at the bottom of the melting pot a 

 h;ii-d porous mass is found, melting at the same temperature with 

 zinc. Made quite liquid, and then chilled. Babbits metal becomes 

 nearly amorphous, sonorous and very smooth when filed or turned. 

 Nevertheless it will stick to an axle, even when liberally lubricated, 

 and when heated to softening it is liable to recrystallization, crystals 

 being formed in a groundmass of liquid tin. Tinning of the axle, 

 sticking, and as an inevitable consequence heating will occur, when- 

 ever a heavily weighted axle is run in a box filled with such 

 metal. Finally recrystallization sets in and liquid tin is squeezed 

 out, the newly formed crystals accumulating around the axle. In 

 one case the crystals had formed a compact cylindrical layer, at 

 first sight puzzling, but now easily explained. 



With a view to test this theory, experiments were made with 

 model cushion blocks, cast under varied conditions. The blocks were 

 fitted on a mandril of polished steel, running with a speed of 1600 

 revolutions per minute in a wooden casing. The apparatus was 

 contrived in such a manner, that the pressure on the mandril could 

 be varied at pleasure and the temperature observed on a thermometer 

 fitted into the blocks. The following table gives for some of the 

 experiments the pressures reduced to kilogrammes on the square 

 centim. of the longitudinal section of the mandril and the mean 

 increase of the temperature after a minute of running. Block I was 

 cast in a mould, cooled by running water, block II in a mould 

 heated to 100°, block III in a mould heated in molten zinc. 



