472 



SUMMARY OF CURRENT RESEARCHES RELATING TO 



66 seconds, it may be assumed that the quantity reduced in one second is 

 0-20 per cent. If this quantity be taken as the unit of activity of reduc- 



FiG. 115. 



tion, then the following formula gives the activity corresponding to any 

 values of the time of reduction and quantity of oxyhremoglobin determined 

 by the above methods. 



_ quantity of oxyha3moglobin k 



time of reduction 



Activity of reduction e = 



Hayem's Chromometer. — Prof. G. Hayem's apparatus for measuring 

 the quantity of hfemoglobin in the blood consists of two cells arranged on 



Fig. 116. 



a slide as in fig. 116, one of which is filled with dilute blood and the other 

 with pure water, the slide being placed on a standard colour for com- 

 parison. 



Spectrum Analysis in Micro-Mineralogy* — Dr. K. de Kroustchoff 

 believes that he has found a method which, by the aid of spectrum analysis, 

 will allow quantities that are unrecognizable by ordinary means to be easily 

 identified. For this purpose he uses an apparatus which consists of a glass 

 cylinder closed at both ends by a brass cap. In the upper cap is a stuffiug- 

 box, through which a brass rod, with a platinum point for an electrode a, 

 plavs up and down. Through the upper cap also pass two brass tubes, 



* Bull. Soc. MiiRi-al. Frnnce, vii. (18S4) pp. 243-9 ({ pi.). 



