718 



SUMMARY OF CURRENT RESEARCHES RELATING TO 



acts as a hinge and allows the large slip to be turned over. A small 

 wire clip is used to hold the covers firmly to the slido in either 

 position. 



(6) Miscellaneous. 



New Counting- Apparatus for Plate Cultures.* — E. Thiele de- 

 scribes a counting apparatus which is intended to avoid counting the 

 colonies twice over. It consists of a tripod stand having a loup attached 

 to the upper end of the pillar. This loup has a diameter of 10 cm., 

 gives a magnification of six to eight, and can be used with both eyes. 

 The plate is borne on a carrier which can be moved up and down the 

 pillar. The carrier is marked out in squares or in sextants. The dis- 

 tance between the loup and the carrier is such that a pencil canjbe 

 used to indicate the colonie?. 





"»»Ba»»«S<BKX5fg55»5 



Fig. 146. 



Effect of Reheating upon Overheated Steel.f — K. F. Goransson 

 concludes that the destruction of the coarse network of cenientite is 

 caused by its carbon being dissolved in the martensite, and that the 

 network surrounding the new grains is formed by the expulsion of 

 cementite from the martensite as it is being cooled. 



Steel Rails : Relation between their Structure and Durability. { 

 R. Job has undertaken a long series of microscopic observations on 



* Centralbl. Bakt., 2 te Abt., ix. (1902) pp. 332-3 (1 fig.). 

 1- Metallographist, v. (1902) pp. 216-28. 

 t Tom. cit., pp. 177-91 (13 microphotos). 



