QUEKETT MICROSCOPICAL CLUB. 357 



table of the epidiascope and projected on to the screen during the 

 various operations. A drop of glycerin is placed in the centre 

 of a slip, the objects are withdrawn from the store solution and 

 arranged in the drop, particles of dirt or bubbles being lifted out 

 with a stout needle. Thin card squares are then placed so as to 

 form an equilateral triangle with the drop of glycerin in the middle. 

 The squares should be placed so that they will be fairly near the 

 edge of the cover, and one should be equidistant from the sides 

 of the slip. Near this square is placed the semi-disc of wax, 

 the slip is held horizontally over the spirit lamp and slowly rotated 

 so that the flame travels round under the periphery of the cover 

 glass. As soon as the wax has run in, remove the flame, and in a 

 few seconds the wax will have set, so that the surplus may be 

 scraped away and the slip wiped clean. The placing of the wax 

 close to the card square prevents the cover tilting as the wax runs 

 in. Twenty or more small obj ects may be arranged symmetrically 

 in a drop of glycerin, and subsequent operations wiU not disturb 

 them. Several drops of glycerin may be mounted under one 

 cover, and the wax will isolate and seal them ; in this case a card 

 square should be put between each drop and the next. If it is 

 desired to raise the cover glasses at any time, slides may be left 

 unringed, but for greater permanency several coats of gold size 

 should be applied. Covers may easily be removed from unringed 

 slides by cutting through the wax with a thin sharp knife or 

 safety razor blade. Slides should be kept in a warm place — 

 i.e. do not let the temperature fall much below 50° F. They 

 should be examined periodically, and if any signs of want of 

 adhesion between the wax and the glass appear, the slide may 

 be gently heated until they disappear without disturbing the 

 ringing cement. Mr. Curwen said that out of 500 slides he had 

 made by this method during the last two years, only thirteen 

 had been scrapped owing to faults developing. Mr. Curwen 

 exhibited an electric heater for running in the wax, consisting 

 of a coil of nichrome wire, through which an electric current 

 could be passed, bent into a circle and attached to a plate of mica. 

 After the paper had been read, a series of photomicrographs of 

 objects mounted by the method described was shown on the 

 screen. The subjects chosen were mostly Entomostraca, but the 

 wider application of the method was indicated by a few photo- 

 graphs of other specimens mounted in the same way. 



