ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 505 



New Fluid for the Haemocytometer.* — A. Edington has prepared 

 the following solution for use with the haemocytometer : neutral citrate 

 of sodium 7"5grm., formalin 2 c.cm., dahlia 0*03 grm., chloroform 

 5 drops, distilled water 250 c.cm. Mix the stain with the water, and 

 then add the citrate and formalin. Leave for a few days, and use the 

 supernatant fluid ; if necessary, filter before use. 



Walton, L. B. — Contributions to Museum Technique: Cataloguing Museum 

 Specimens. 



[Gives a description of a practical method of registering specimens by means 

 of the card system.] Amer. Naturalist, xli. (1907) 



pp. 77-96 (3 figs.). 



Lee, a. B.,'u. P. Mayer — Grundzuge der mikroskopischen Technik fur Zoologen 

 und Anatomen. Berlin : R. Friedlander u. Sohn, 3rd edition, 



1907, vii. and 522 pp. 



Metallography, etc. 



Cadmium-bismuth Alloys.f — A. Portevin has determined the equi- 

 librium diagram of this series. The metals were melted together in 

 ■glass tubes in a ciu'rent of hydrogen and cooling curves taken, a thermo- 

 couple being used. Tammann's method for determining the quantity 

 of eutectic in each alloy was employed. The equilibrium diagram 

 obtained is very simple. I\o compounds or solid solutions occur ; two 

 branches meet at the eutectic point 138° C, 63 p.c. cadmium. The hori- 

 zontal eutectic line extends completely across the diagram. Microscopic 

 study of the series showed that the alloys consisted of eutectic, together 

 with either acicular crystals of cadmium or cubic crystals of bismuth. 



Iron and Arsenic.^ — K. Friedrich has determined the equilibrium 

 diagram and investigated the microstructure of the range of alloys from 

 !il • 6 to 44 • p.c. iron. Five crystalline phases were distinguished. The 

 author has demonstrated the existence of the compounds FcoAs and 

 FcaAso, and considers that of FeAs as probable. The nature of two 

 phases, one apparently containing more than 90 p.c, the other 48 * 3 p.c. 

 iron, remains in doubt. With the first of these Fe^As forms a eutectic 

 at 70 p.c. iron and 830° C. FcgAsa is the product of a chemical 

 reaction occurring in the solid state at 800° C. The freezing point of 

 FcoAs is 919° C, that of FeAs about 1030^ C. No indication of the 

 formation of FcgAs was obtained. The conclusions drawn from the 

 freezing point curve were confirmed by microscopic examination of the 

 alloys. 



Nickel and Arsenic.§ — The equilibrium diagram of the series of 

 alloys, containing from 0-57*4 p.c. arsenic has been determined by 

 K. Friedrich. Owing to the complexity of the diagram — 15 fields are 



* Lancet, 1907, ii. p. 86, 



t Rev. de M6tallurgie, iv. (1907) pp. 389-94 (6 figs.). 



X Metallurgie, iv. (1907) pp. 129-37 (19 figs.). 



§ Tom. cit., pp. 200-16 (37 figs.). 



Aug. 21&t, 1907 2 l 



