248 Scientific Intelligence. 



were evolved under these circumstances in amounts exactly cor- 

 responding to the equation 



(NH 4 ) 3 S0 4 + 2H a S0 4 = N s + 3SO, + 6H 2 0. 



The part played by the platinum in the reaction is shown by the 

 following equations : 



4H„S0 4 + Pt = Pt(S0 4 ) 2 + 2SO„ + 4H 2 ; 



3Pt(S0 4 ) 2 + 2(NH 4 )JS0 4 = 2N 2 "+3Pt + 8H 2 S0 4 . 



The truth of this interpretation was shown by the fact that a col- 

 ored solution is obtained by treating platinum with sulphuric 

 acid, and that this solution deposits most of its platinum when it 

 is heated with ammonium sulphate. There is a further, indirect 

 proof in the fact that sponges of metallic gold and iridium, which 

 do not dissolve in sulphuric acid, cause no loss of ammonia under 

 similar treatment. — Bulletin, xxxv, 8. h. l. w. 



3. The Determination of Tellurous and Telluric Acids. — To 

 make these determinations Berg places the substance in a porce- 

 lain boat in a combustion tube which is drawn out in front, bent 

 downward, and connected with two small U-tubes each contain- 

 ing 5 CC of water. Gaseous hydrochloric acid is then passed 

 through the tube, and when the air has been expelled, the tube 

 is rapidly heated below redness, while the current of gas is moder- 

 ated, and thus tellurous chloride is formed and collected in the 

 receivers. The liquid is transferred to a weighed porcelain cap- 

 sule, 5 CC of pure nitric acid are added, the liquid is evaporated 

 on a sand bath, and the residue is heated cautiously to decom- 

 pose the basic tellurous nitrate without fusing the resulting 

 oxide. Tellurous oxide is then weighed. When certain salts are 

 thus analyzed, the metallic chloride remaining in the boat may be 

 weighed. The author gives some satisfactory results obtained 

 by this method. — Bulletin, xxxiii, 1310. h. l. vv. 



4. Manganese as a Fertilizer for Plants. — The view was 

 formerly held that the small quantities of manganese present in 

 vegetable and animal substances were accidental and unnecessary, 

 but recently many investigations have indicated that this metal 

 is indispensable to the living cell. Bertrand has recently shown 

 by field experiments that the application of pure manganese sul- 

 phate to the soil at the rate of 50 kg per hectare showed a marked 

 fertilizing effect upon a crop of oats, amounting to an increase of 

 22-5 per cent in the yield. An analysis of the crops to which 

 manganese was applied showed no increase in its contents of the 

 metal over the crop to which none was applied. — Comptes Rendus, 

 cxli, 1255. h. l. w. 



5. Conversations on Chemistry, by W. Ostwald. Authorized 

 translation by Stuart K. Turnbull. Part II, The Chemistry of 

 the Jlost Important Elements and Compounds. 12mo, pp. 373. 

 New York, 1906, John Wiley & Sons. — The first volume of this 

 work, by another translator, was recently noticed in this depart- 

 ment of the Journal. Like its predecessor, the second part has 

 many interesting and excellent features, and if the old conversa- 



