2 INTRODUCTION. 



Take a block of wood about 10 cm. long and 6 cm. 

 wide. Fix upright in the middle of the block about 

 2 cm. from one end a bit of metal rod of 3 to 4 mm. 

 diameter and 6 to 8 cm. high. Bore a hole a little to 

 one side of the center of a smooth cork so that it will 

 slide smoothly on this rod. Bore another hole at right 

 angles to the first through which pass a wire of 7 to 8 

 cm. length. The free end of this wire may be bent into 

 a loop or circle as maybe desired to hold the lens. 1 The 

 lens may be focused by sliding the cork up or down. 

 Cheap loupe holders are also to be had of dealers in 

 optical goods. 



The mounted needles can. be better made than bought. 

 Take two number 8 " sharps," break off about one-third 

 of the needle from the blunt end and grasping the remain- 

 der firmly with a pair of pliers, push the blunt end into 

 a pine pen-holder or any suitable piece of soft wood 

 till firm. The points of the needles should be kept 

 sharp. 



The razor should be of the best quality of steel 

 without any stamped lettering or even etching on the 

 blade, which should be at least 2 cm. wide. The 

 best shape for the blade is to be ground flat on the 

 under side (when held in the right hand with the edge 

 toward one) and hollow on the upper. Next to this 

 shape the "hollow ground " razor is best, provided the 

 thin part of the blade is at least 12 mm. wide and not 

 so thin as to be easily bent. " Extra hollow ground " 

 razors have the blade too thin. 



Glass slips with ground edges may be purchased of 

 any dealer in microscopical supplies or they maybe cut 

 1 Modified from Kingsley, The Naturalist's Assistant, p. 83. 



