INVERTEBRATA, CRYPTOGAMIA, MICROSCOPY, ETC, 507 



with facility in this manner. The various tools sold by hardware 

 dealers for cutting washers of leather, &c., have often been em- 

 ployed for this work, but they have proved too clumsy to be useful. 



How to make the new Wax Cell.* — Dr. F. M. Hamlin uses for 

 making the wax cell, " which has so suddenly come into favour," only 

 a turntable and a penknife. Placing the slide upon the turntable, 

 a square or circular piece of sheet wax (such as is used in making 

 artificial flowers) is put upon the slide and carefully centered. The 

 outer edge should then be pressed firmly upon the glass with the 

 thumb or fingers. Having determined the exact size of tlie cell, turn 

 the slide very slowly and hold the knife with the blade slightly 

 moistened so that the point will cut from the upper surface of the wax 

 downward and outward, gradually pressing the point of the knife 

 down upon the glass. This manner of holding it causes it to serve as 

 a wedge, the outer shaving of wax being generally thrown up and 

 entirely off the glass. If a circular piece of wax from a punch is 

 used, its outer edge should be trimmed off to make it perfectly circular, 

 the pressure of the fingers being likely to distort it somewhat. Any 

 superfluous wax that may remain may be removed by means of a bit 

 of cloth held over the end of the finger or on a stick. 



The next operation is to cut out the centre, and is done in the 

 same way, only that the knife is held so as to ciit from the toj) of the 

 wax downward and inward, toward the centre of the cell, so that the 

 bottom of the wax ring shall be wider than the toji, which should be 

 about one-tenth of an inch in width. As the point of the knife 

 goes down it throws up the different thicknesses of wax till the last is 

 reached, which it removes, leaving the glass inside the ring almost 

 perfectly clean, unless too much pressure has been used in fastening 

 the wax to the slide. 



These wax cells possess certain advantages over others, among 

 which is the slight cost of the necessary apparatus for making them. 

 It might be thought that wax alone is too soft for durable moimts, but 

 this is not the case. Being made and fastened upon the slide at one 

 operation, they are not liable to that distortion which removal from 

 the punches is likely to cause. They can also be made of any size. 



According to Mr. C. C. Merriman the wax must be carefully covered 

 with some cement, whether used for fluid or dry mounts ; as it is 

 said that certain volatile portions will ultimately collect upon the 

 glass cover of dry mounts or mingle with the preservative media in 

 liquid mounts, and thus spoil the work in either case His experi- 

 ence is, that the best cement to cover the wax with is Miiller's liipiid 

 marine-glue. After coating the ring with this it is used in the 

 ordinary way. 



Device for Mounting.t — Mr. A. L. Woodward applies to a Cox 

 turntable a slender arm of brass which is attached at ono end to tho 

 hand-rest of the turntable by a millod-hcad screw. Tho other end 

 extends over tho centre of the turntable at a suitable height abovo 

 it. A pointed screw comes down through tho end of tho arm exactly 

 over the central dot. In mounting in glycerine, fov example, after 



* ' Am. M. MiiT. Jouiu.,' i. (1880) p. IH. t If'i'l- V- S^- 



2 L 2 



