Melting Points of Certain Metals. 



505 



plicity of construction and certainty of operation, it seems 

 desirable to describe it more fully. 



The end of the pipe p is turned off at an angle of 60°; a 

 small round nut is put on, using a left-handed thread, and the 

 whole is held in place by means of the larger nut n, which is 

 undercut to receive the smaller nut. The end of the pipe fits 

 into a conical hole also turned accurately at au angle of 60°. 

 An essential part of the procedure is that before the joint is 



Fig. 2. 



CMS. 



Fig. 2. Details of high pressure valve and connections, drawn to scale. 

 The main bod}" of the valve is of best quality nickel steel. The conical 

 lower end of the valve spindle s fits into a conical depression. The leather 

 packing around the spindle is held down by the nut m. On either side of 

 valve is shown the type of high pressure connection which has been used for 

 joining various parts of pressure apparatus. The end of the pressure pipe 

 p is turned off at 60° and fits pressure-tight into a conical depression. A 

 small round nut is screwed onto the end of the pipe and the whole is held 

 down tight by means of the larger nut n. 



assembled for the first time, the pointed end of the pipe should 

 be given a blow with a hammer squarely on its end. This 

 treatment enlarges the tip slightly and has the effect of making 

 certain that when the end of the pipe is forced into its seat by 

 screwing up the nut m it is the extreme tip that binds on the 

 surrounding metal. This type of joint may occasionally leak 

 when pressure is applied for the first time ; increase of pres- 

 sure, however, makes the joint tight by expanding the tip of 



