360 SUMMARY OF CUERENT RESEARCHES RELATING TO 



preserved from rust by simply rubbing a few drops of kerosene oil 

 over them with a soft cbamois-skin, and then placing tbem in a tightly 

 corked phial. 



The size of the objects to be examined under the Microscope 

 may vary considerably ; but the sizes found most convenient range 

 from 1/4 in. down to about 1/16 in. in thickness, and from 1 in. to 

 1/5 in. in sectional area. If the specimens are extremely thin, 

 there is often much difficulty in mounting them properly on a slide, 

 and in getting the etched surface perfectly parallel to the object-glass. 

 After the surface has been sufficiently treated with acid, and shows 

 under the Microscope no further traces of scratches made in the 

 grinding, it should be carefully dried and cemented to a glass slide 

 with wax or cement, great care being taken to have it in the proper 

 plane parallel to the object-glass : otherwise, it will be impossible to 

 make a satisfactory photograph. 



The great difficulty encountered in pursuing the study of the 

 structure of materials is that of making accurate and satisfactory 

 records of what is seen under the Microscope. To effect this, the 

 only accurate and quick means is to photograph. Hence the student 

 must not only be a good microscopist, but also understand the theory 

 and practice of photography, an accomplishment which every engineer 

 will find it useful to acquire." 



Some hints are given for photographing and for selecting a 

 Microscope. The use of a condensing lens depends, it is said, upon 

 the ability of the etched surface to reflect light. Thus hard steel 

 reflects light so well that a condenser is not necessary, while in the 

 case of pig, cast, or wrought iron its use is absolutely essential. 

 Ten photographs are given of various kinds of iron and steel, with a 

 description of the characteristic features of the specimens. 



Draper's Graphic Microscopy. — Mr. E. T. Draper proposes to 

 continue in a separate form the coloured illustrations which vrere a 

 special feature of ' Science-Gossip ' in 1884 and 1885. The first 

 part has been issued with two plates and accompanying description. 

 Mr. Draper is well known as one of the most expert artists in draw- 

 ing microscopical objects that we have, and we shall be very glad to 

 hear that his new venture turns out a remunerative one. For this it 

 is necessary that microscopists— who cannot but appreciate such work 

 — should give it more than moral support. 



Banti, G. — Manuale di Technica Batteriologica. (Manual of Bacteriological 



Technique.) From Lo Sperimentale, May, 1885. 



Baeeggi. — Modificazione all' allestimento del preparati Microscopici tinti con 



colori di anilina alio scopo di renderne piu perfetta e durevole la conservazione. 



(Modiiication in preparing microscopical objects stained with anUin colours 



iu order to make them more durable.) [^Post."] 



Gazzetta degli Ospitali, 1884, p. 645. 

 Bellonci, J. — La terminaison centrale du nerf optique chez les mammiferes. 

 (The central termination of the optic nerve in mammals.) 

 [Methods, post.'] Arch. ltd. de Biol, VI. (1885) pp. 405, 



Bel VCR.— On staining in toto the Central Nervous System with Weigert's 

 HaematoxyUn. \^Post.'\ Brain, 1885, July. 



