530 Chronicles of Science. [Oct., 



of butter is obtained, which according to the author is a true 

 amalgam of mercury and hydrogenium. The author describes at 

 length several reactions of this body, which in many of its pro- 

 perties is akin to hydrogenium-paUadium. Professor C. A. Seeley, 

 speaking of this amalgam and the allied ammonium amalgam, gives 

 it as his firm opinion that they are only mechanical mixtures of 

 mercury and gases. In illustration of this he describes an im- 

 portant experiment to prove that if ammonium amalgam be subjected 

 to varying pressure, its volume changes, apparently, in accordance 

 with Mariotte's law of gaseous volume. To illustrate this, a glass 

 tube |- inch in diameter, 20 inches long, and fitted with a plunger, 

 was employed. Mercury containing a little sodium was poured 

 into the tube to ^ inch in depth ; and upon this was poured a strong 

 solution of chloride of ammonium occupying about 2 inches in 

 length of the tube. The ammonium amalgam was completely 

 formed in a few minutes, and occupied several inches of the tube. 

 On adjusting and depressing the plunger, the volume of the 

 amalgam progressively diminished till it closely approached the 

 original volume of the mercury. Also, it was notable that 

 the amalgam progressively gained fluidity and the mirror surface 

 till, at the greatest pressure, the original volume and appearance of 

 the metal were resumed, whilst on reducing the pressure below 

 that of the air, the amalgam still expanded until it rose above the 

 surface of the liquid in ihe tube. If the great pressure be main- 

 tained, more ammonium amalgam will be formed, the mass expand- 

 ing progressively, apparently in accordance with the fact that the 

 absorption or adhesion of gases to liquids is favoured by pressure. 

 By means of the simple apparatus used, a pressure of ten atmo- 

 spheres or a good vacuum are easily and at once obtainable, and the 

 experiments with it are very striking. The considerations regarding 

 ammonium amalgam are evidently equally applicable to Loew's 

 hydrogenium amalgam ; both may be only metallic froths. The ex- 

 pansion of palladium observed by Graham, on its absorption of hydro- 

 gen, is probably analogous to the case in question. In both cases, 

 the gases concerned are condensed, by reason of their attraction 

 to the metal ; and if the molecules of palladium were made free 

 to move, as those of mercury, it is probable that Graham's hydro- 

 genium alloy would become a palladic froth, more remarkable than 

 the corresponding mercuric froth. 



The presence of manganese as an essential constituent of milk 

 and blood (human as well as animal) has been known for about 

 twenty years past, but E. Pollacci gives some particulars about the 

 method of detection of this metal in the two animal fluids referred 

 to. The milk which contains this metal in the largest proportion 

 is first evaporated to the consistency of a paste ; this is carbonized 

 by heat in a platinum crucible; the charcoal thus obtained is 



