ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 631 



Various pigments are enumerated, greens and blues (0*05 p.c. in 

 83 p.c. alcohol) being the most suitable. The actual stain, however, 

 appears to be less important than the rest of the technique. By this 

 method rice starch-grains are distinguished from those of wheat by the 

 distinct, relatively large and reddish hilum. 



Simple Formula for Mixing any Grade of Alcohol Required.*— 

 E. W. Berger gives the following : Let P represent the grade per cent, 

 of the alcohol on hand, P' the grade per cent, required, v the number of 

 volumes of water to be added to one volume of P to make alcohol P', 

 and x the number of volumes of P we desire to change to P'. Then 



Fx = p , 



X + vx 

 From this we get 



F v = P - P' 

 and 



P^-F 



Microscopic Slides in Drawers.f — R. Inwards writes : In taking 

 slides from the drawers in which they are kept, there is often some 

 difficulty in getting the finger under the edge of the slide so as to lift it 



Fig. 74. 



out. This is especially the case when the slide nearly fits its recess. 

 The sketch (fig. 74) shows the plan I have adopted. A is the slide in 

 its drawer ; B is a piece of silk cord T V in. in diameter, fastened with 

 seccotin to the bottom of the drawer inside and at 'f- in. distant from 

 the front. A slight pressure at C raises up the other end of the slide, 

 which can then easily be taken out. The sketch shows the slide tilted 

 up ready for removal. At other times it lies nearly flat in the bottom 

 of the drawer. 



Apparatus for Rapidly Cleansing Sand and Gravel.J — W. Lorch 

 has devised an apparatus (fig. 75) for cleansing sand and gravel, 

 material so often required in botanical researches. It consists of a 



* Ohio Naturalist, vi. (1906) pp. 352-3. 



t English Mechanic, lxxxiv. (1906) p. 18 (1 fig.). 



X Flora, xcvi. (1906) pp. 525-6 (2 figs.). 



