ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 407 



formulae could be separated ; (2) those in which the residue consisted of 

 the second metal only, no compound being isolated. The first class 

 includes the binary alloys of manganese with aluminium, silver, molyb- . 

 denum, chromium, and vanadium, the second class the alloys with 

 cobalt, nickel, copper, tungsten, lead, platinum, zinc, cadmium, tin, 

 bismuth, and antimony. Some observations on the remarkable magnetic 

 properties of the manganese- bismuth, manganese-tin, and manganese- 

 antimony alloys are recorded. The author fully recognises the pro- 

 visional character of the deductions drawn as to the number and 

 formulas of the compounds existing in each system. 



New Form of Pearlite.* — C. A. F. Benedicks describes as "bead 

 pearlite " an intermediate form between laminated pearlite and the coarse 

 granular pearlite which is obtained by annealing laminated pearlite below 

 the critical temperature. The new form was observed in grey Swedish 

 pig-iron after heating to 670° C, and disappeared on further heating. 

 The structure of the " bead pearlite " appears to indicate its formation 

 by a partial coalescence of the thin lamella? of laminated pearlite into 

 larger masses. 



Heat-treatment of Steel.t — A. Campion describes the elementary 

 properties of steel upon which heat-treatment is based. Time of heat- 

 ing and mass are possibly the most important factors, apart from tem- 

 perature, in determining the structure and properties of the material. 



Arrivaut, G. — Alloys of Copper and Manganese. 



Proct ] s-verbaux cles stances de la SociM des Sciences physiques 

 et Naturelles de Bordeaux, 1907-8, pp. 142-3. 



„ „ Arsenides of Manganese. Tom. cit., pp. 159-62. 



Dccelliez, F. — Cobalt-lead Alloys. Tom. cit., pp. 31-4. 



,, ,, Action of Heat on a Mixture of Arsenic and Cobalt. 



Tom. cit., pp. 57-73. 



„ „ Cobalt-antimony Alloys. Tom. cit., pp. 175-87. 



Yigouroux, E.— Nickel-lead Alloys. Tom. cit., pp. 28-30. 



„ „ Action of Arsenic on Nickel. Tom cit., pp. 48-56. 



n „ Siliciuration of Iron and Manganese. Tom. cit., pp. 78-80. 



„ „ The Arsenides NiAs and Ni 3 As 2 . Tom. cit., pp. 137-41. 



„ ,, Arsenides of Iron. Tom. cit., pp. 155-8. 



„ „ Antimonides of Nickel. Tom. cit., pp. 169-74. 



Yigouroux, E., & Sanfourche — Arsenides of Chromium. 



Tom. cit., pp. 144-50. 



tt „ ,, Arsenides of Silver, Tom. cit., pp. 163-8. 



Rosenhain, W., & P. A. Tucker— Eutectic Research. No. 1, Alloys of Lead. 

 and Tin. 



[A more complete account of the work described in the paper summarised 

 in this Journal, 1909, p. 117.] 



Nat. Phys. Laboratory, Collected Researches, v. (1909) pp. 83-118 

 (42 figs.). Reprinted from Phil. Trans. Boy. Soc, A 209 (1908). 



* Iron and Steel Times, i. (1909) pp. 135-8 (5 figs.), 

 t Tom. cit., pp. 157-66 (14 figs.). 



