The Microscope. ^07 



if underneath, cannot easily be removed. Kather than attempting 

 their removal, return the object to the turpentine and repeat the 

 process with more care. If any arrangement of the parts may be 

 required, use the mounting pair of brashes, dipping them at first and 

 occasionally after in the turpentine to avoid creating babbles which 

 however may, if on the surface, be readily broken by using the point 

 of a needle heated in an alcohol flame. Then ap})ly more Ijalsam 

 over the insect, wipe the under side of the cover glass, held with the 

 pliers in the turpentine, draining off as much as will, then place the 

 cover-glass over the insect, having regard to the centering ring. It 

 must be lowered first at one edge of the cover-glass aud slowly to 

 avoid making bubbles which are not so likely to appear if the balsam 

 is of proper consistency. The moistening of the cover glass also 

 obviates that tendency. It will now be usually found necessary to 

 make some readjustment of the parts or position of the insect. This 

 is often a most tiying process; but may be accomplished with the 

 flattened needle referred to. Holding the pliers perpendicularly, 

 rest on the slip the points spread to span the edges of the cover-glass 

 to hold it in place. Then moistening the needle in turpentine, insert 

 it under the cover-glass and move the insect as desired. For this 

 process the great advantage of having the slip raised on the cnpola 

 of the mounting-box with under illumination will be appreciated. 

 The utmost tenderness of movement with the needle is required to 

 avoid injury to the delicate parts and creating those old enemies the 

 bubbles. "We may now press the cover down and remove most of 

 the suqjlus balsam by the suction of the medium -dropper. 



The previous processes have so flattened the insect that pressure 

 by weight or slip on the cover will not usually be needed. 



The troublesome adjustment with the needle under the cover 

 may be avoided if the insect when placed on the slip adheres closely 

 in all its parts, without tendency of the wings to curl or other parts 

 to project out of the balsam. It may, after proper arrangement, be 

 put aside under some cover, to exclude dust, until the balsam has so 

 hardened that fresh balsam may be applied and the cover-glass put 

 on without disturbing the arrangement. 



Pm-e benzol is in some respects better than turpentine in the 

 mounting work; but is expensive. As good results can probably 

 be had with turpentine. 



The slide may now be put away for the balsam to dry and 

 harden, which may be much accelerated by moderate heat. For this 

 purpose the drying-box described in the catalogue of W. H. 

 Walmsley & Co. is unsurpassed. 



