i88 9 .] 



BOTANICAL GAZETTE. 



183 



Schultze's dehydrating apparatus.— The accompanying figure shows 

 a very convenient and simple arrangement for gradually dehydrating 

 small objects. It consists of a wide-necked bottle (a), into whose neck is 



fitted a short tube (6), and within this a 

 similar but smaller tube (c). In order to 

 prevent these tubes from slipping down, 

 the upper part is widened into a small fun- 

 nel. Each of the tubes has the bottom 

 closed by a piece of parchment paper, 

 which is carefully gummed on. The object 

 to be dehydrated is placed in the tube c, 

 which is partly filled with weak alcohol 

 (about 30 per cent), and this is then placed 

 1 ja j n ^ tu i3 e fy w hich in turn is put into the 



^ J fl____ i l|l_____ neck of the bottle a, which has been filled 



with absolute alcohol. By the diffusion of 

 Dehydrating Apparatus. the fluid through the membranes covering 



the bottom of the tubes b and c, the density of the fluids will finally be- 

 come the same, and the object in c will thus gradually be brought into 

 practically absolute alcohol. The cover, d, effectually prevents evapora- 

 tion and at the same time keeps out dust. 



In order to prevent the alcohol in a from becoming too much di- 

 luted, it is best to use a very small amount of the weak alcohol, and a lit- 

 tle calcined copper sulphate placed in the bottom of the bottle will absorb 



what little water may be present. 



Usually two or three hours is sufficient for completely dehydrating 

 most objects, but naturally large ones may take longer. Of course the 

 process may be expedited by covering the bottom of only one of the 

 tubes with the membrane, but it is usually better to have the diffusion 

 take place rather slowly.— Douglas H. Campbell, Bloomingion, Ind. 



CURRENT LITERATURE. 



Forms 



Prof. Penhallow has presented in this short memoir a most valuable 

 contribution to our knowledge of one of the oldest and most perplexing 

 forms that has claimed the attention of paleobotanists. The original ma- 

 terial was collected bv Sir W. E. Logan, from the Erian sandstones of 

 Gaspe, about 1S52. It was first examined by Dr. (now Sir) William Daw- 

 son in 1855, who recognized at once the extreme interest attached to the 



[ Penhallow. D. P.-On Nematophyton and Allied Forms, from the Devonian of 

 Gaspe, with introductory note a by Sir William Dawson. Trai Roy. Soc. Canada. '^ ol. 



VI. Sect. IV, 1888, pp. 27-47. PL I, II. 



