128 PROCEEDINGS OF THE SOCIETY. 



" Four of the ring gauges are slightly bell-mouthed, and measurements 

 have been made of the smallest diameter, which occurs towards the 

 centre of the gauge, and also of the diameters towards the faces of the 

 gauge. The latter measurements were made at about |- inch from the 

 faces, and, therefore, owing to the taper, the diameters at the faces will 

 be slightly larger than the values given. This is also evident from the 

 tit of the plugs in the rings. In several cases the plug is found to enter 

 a short distance at each face and then pull up well before the end of the 

 plug has passed half-way through the ring." 



The Council of the Society does not propose to have new standard 

 reference gauges constructed for eye-pieces, as any maker can have, if 

 he requires it, his own limit gauges checked at the National Physical 

 Laboratory. 



Attention is drawn to the fact that the Eoyal Microscopical Society's 

 Standard Object Glass Screw Thread Gauges are still deposited with the 

 National Physical Laboratory, and the Society has on sale special 

 verified taps and dies for sizing the objectives and nose-pieces of 

 microscopes. 



