ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 



785 



(5) Mounting-, including 1 Slides, Preservative Fluids, etc. 



Newton, A. — Preparing Insects and Parts for Mounting in Balsam. 



Trans. Manchester Micr. Soc, 1909, pp. 79-80. 

 H. M. C. — Mounting Slides. 



English Mechanic, xc. (1909) pp. 165, 189-90, 212 



(6) Miscellaneous. 



Micrometer Attachment.*— S. A. McDonald describes the following 



modification of the ordinary micrometer. A piece of brass tubing (fig. 128) 

 is reamed out to make a sliding fit on the anvil of the micrometer. The 



Fig. 128. 



tubing holds loosely a £ in. bicycle ball, which extends beyond the end 

 of the tube, the latter being bent over to prevent the ball from falling 

 out. The reading is taken from the 0*250 in. graduation as zero. 



Metallography, etc. 



Meteoric Iron.f— W. Fraenkel and G. Tammann have studied two 

 pieces of meteorite containing respectively 7 '8 and 9 p.c. nick el 

 Sections were examined, after heating to different temperatures under 

 conditions which almost entirely prevented oxidation. The temperatures 

 of magnetic transformation were also determined. Attempts were made 

 to reproduce artificially the structure of meteorites, but without positive 

 results. Long heating of meteoric iron at 420° C. causes the kamacite 

 to granulate ; it would therefore appear that meteoric nickel-iron alloys 

 are unstable at the ordinary temperature. The constitution of meteorites 

 and the causes of the structural differences between meteorites and alloys 

 of the same composition prepared by melting the metals together, are 

 fully discussed. Possibly, as in the case of chromium and molybdenum 

 steels, changes take place in the molten state dependent on the maximum 

 temperature attained, and the characteristic constitution of nickel-iron 

 meteorites may be due to the attainment of an exceedingly high tem- 

 perature at some period in their history. 



Gruillernin has examined 

 p.c. graphite, 



Structure of "Steely" Cast Irons.J 

 microscopically four cast irons 



containing 2 ■ 6 5-2 ' ! I ."> 



* " Machinery," see English Mechanic, xc. (1909) p. 178. 

 t Zeitschr. Anorg. Chern., lx. (1908) pp. 416-35 (27 figs.), 

 j Rev. Metallurgie, vi. (1909) pp. 946-50 (12 figs.). 



