THE society's NOTE-BOOKS. 117 



ference thus : — If you look at a room through the window, you 

 can see a great deal of everything therein ; but if one were to see 

 only a thin section of any part, all that would be noticed would 

 be the walls, the profile of mantel-piece, of some part of a chair, 

 a table, etc. In like manner one can recognise the shape of a 

 glass tumbler when one sees it whole, but a section merely 



shows I I ; hence it is that a section of wood made longitudinally 



is better when thick than when made very thin. In one case one can 

 well recognise the nature and size of the dotted ducts ; in the 



other one merely has a serrated outline, -^ ^~^-.^-_ Qf course, 



one must always seek to get sufficient transparency to permit 

 light to pass. I have a beautiful section of jet, which shows lines 

 radiating in all directions from a centre towards the eye — away 

 from it and laterally ; but these can only be shown by a strong 

 light condensed. If I were to thin the specimen, I should lose either 

 the centre or the lines which radiate to or from the eye. 



J. Inman. 



Glycerine Jelly v. Canada Balsam for mounting Entomolo- 

 gical slides. — I am glad to find that some agree with me that 

 " clearness of specimens is not the perfection of mounting." Let 

 anyone mount two specimens of the same object, one in C. Balsam 

 and the other in G. jelly, and compare them. The Balsam one 

 will be perhaps as clear as glass, of a very pretty colour, varying 

 between amber, yellow, and sepia ; the Glycerine jelly mount will 

 at first-sight look woolly, and not nearly so pretty in colour as the 

 former ; but on closer inspection, the jelly mount will show far 

 more detail than the other. The woolliness is 77ot in the jelly, for 

 it is as clear as the balsam, nor is it dirt, for the effect is the same 

 in the most perfectly cleaned specimens. It must, therefore, be in 

 the objects themselves, and surely no one would willingly conceal 

 the characteristics of his specimens for the sake of prettiness. 



r. J. Allen. 



Cement.— Brunswick Black and Gold Size in equal proportions 

 I have found a worthy cement for fastening down covers on cells 

 in dry mounts. It is far superior to Brunswick black alone, and 

 is a cement requiring little or no trouble in preparation. I have 

 tried it for glycerine jelly mounts, and in most cases it has answered 

 well. It is best for this class of objects if the size is <?/^ when 

 mixed, as it is not so fluid, and therefore less liable to run in. 



J. C. Hope. 



Cement— Kay's Coaguline is in my opinion the best for fixing 

 cells and for dry mounts. I find it is often desirable to put a ring 

 of it on slides other than dry mounts, thereby cementing together 

 both cover and slide. The advantages of coaguline are — i. That, 



