1909.] 



SIMILAR TO ROWLAND'S METHOD. 



167 



The swivelling joint which functioned excellently, is made very 

 simply of ^-inch gas pipe T's and nipples, as shown in Fig. 2. The 

 lower nipple A'" is screwed tight into the T, but all but tight into 

 the carriage D, so that the rod ab turns in the screw N, kept oiled. 

 Similarly the nipple A''" is either screwed tight into the T (in one 



'^ FlQ i 



'9 



Ja 



Fig. I. Plan of apparatus. A A, BB, slides; C, D, carriages; 

 R, connecting rod. 



method, revoluble grating), or all but tight (in another method, sta- 

 tionary grating), so that the table tt, which carries the grating g 

 may be fixed while the nipple N" swivels in the T. Any ordinary 



