BY N. A. COBB. 167 



EXPLANATION OP THE FIGURES. 



a. — Reservoir used in transferring to lighter fluids. 



a'. — Reservoir used in transferring to heavier fluids. 



b. — Object-box, or object-cylinder. 



c— Filter. 



d. — Short piece of glass tubing. 



e. — Patch of finest linen. 



s. — Capsule. 



t. — Capillary neck to capsule, fine to be fused. 



u, — Mouth of capsule stopped with glue. 



V. — Plug of cotton. 



Figs. 1 and 2. — Differentiator, one-fifth convenient size, with the three 

 parts fa, h, and c) joined in place by caoutchouc tubing. 



Fig. 3.— Object-box (b), and filter (cj, full size, showing the best form 

 of filter. 



Fig. 4. — Object-box, full size, showing best method for securing minute 

 objects. 



Figs. 5 and 6. — Two stages in the process of making a suction-capsule. 



Fig. 7. — Suction capsule ready for use, magnified ; seen in section. 



