MATERIALS FOR BITS. 31 



steel " and "forged steel" to such bits, are careful to suppress 

 the adjective " cast," when alluding to their annealed cast 

 iron wares ; or they craftily call them " malleable iron," 

 instead of " malleable cast iron." As the : leading manufac- 

 turers of bits use special trade marks to show the nature 

 of the articles they make, a purchaser will be guaranteed 

 from fraud in this respect if he has a knowledge of these 

 marks, which unfortunately are generally kept as trade secrets 

 for obvious reasons. Failing this special knowledge, a buyer 

 will have to trust to the honour of his saddler, which he can 

 safely do in the case of several representatives of the trade. 

 The great objection to all cast bits is that bubbles form in 

 metal during the process of casting, and that neither the 

 presence nor the size of these bubbles can be ascertained 

 by ordinary outward inspection. Consequently, an annealed 

 cast iron bit is not only composed of a weaker material 

 than a forged steel one, but its strength is more or less 

 impaired by the inevitable presence of cavities in its substance. 

 We learn from a leading article in Saddlery and Harness 

 of February, 1894, that "the commonest cast iron article , 

 when annealed, can be finished so dexterously, so beautifully 

 that no expert could tell it from a forged steel one, without 

 testing it by making it red hot." As explained in a sub- 

 sequent issue of that' journal, the test for distinguishing 

 between forged and cast iron articles is an extremely 

 simple one, and is carried out by making the suspected 

 article red hot and then beating it with a hammer, in 

 which case a cast iron article will crumble, but a forged 

 iron or forged steel one will not break up. This valuable test 

 is in accordance with the fact that cast iron will not weld- 

 A bit of annealed cast iron, and especially one of ordinary 

 cast iron, will be liable to break, if struck sharply with a 

 hammer when cold ; but one of forged steel or forged iron 

 will remain intact. In cast iron, whether annealed or not, 



