Chemistry and Physics. 159 



chlorate thus, K 2 Mn0 4 + Cl a =(KCl) 2 + Mn0 2 + O s . Indeed he has 

 found that on passing chlorine into the residue obtained by heat- 

 ing potassium permanganate, this residue being heated in the 

 vapor of mercury, the chlorine is absorbed and oxygen is evolved. 

 But here however the action goes further, the manganese being 

 also transformed in part into chloride. That this change does not 

 take place in the preparation of oxygen is evident from the fact 

 that the solution obtained by extracting the residue with water 

 does not contain manganese ; and moreover, manganous chloride 

 in presence of potassium chlorate at a high temperature is im- 

 mediately converted into an oxide with evolution of chlorine. 

 The absorption of the chlorine by the manganate too accounts for 

 the very small quantity of chlorine finally obtained, amounting 

 in the author's experiment to only 6 per cent of the peroxide as a 

 maximum, and this in an exceptional case ; the probable average 

 being not over one per cent. — J. Ghem. Soc, lv, 184, April, 1889. 



G. E. B. 



3. On the synthesis of Formic aldehyde. — Jahn has succeeded 

 in effecting the direct synthesis of formic aldehyde in a very simple 

 manner. In the course of his investigations upon the volumetric 

 determination of hydrogen by means of palladium he observed 

 that the presence of carbon monoxide exerted a disturbing action 

 upon the occlusion of the hydrogen. Attributing this effect to 

 the possible direct union of the carbon monoxide with the hydro- 

 gen under these conditions, he repeated his experiments with 

 suitable modifications and passed a mixture of carbon monoxide and 

 hydrogen over palladium sponge, and then through potash bulbs 

 containing water. Although very little condensation took place, 

 apparently, the water acquired a weak odor of aldehyde ; and the 

 solution, obtained from two liters of the gas mixture, gave very 

 distinctly the reducing action characteristic of aldehyde and pro- 

 duced an excellent silver mirror. In view of the synthesis of the 

 sugar formose C 6 H 12 6 by Loew by the action of calcium hy- 

 drate on formaldehyde, this synthesis of the latter substance 

 makes it possible to build up a glucose very directly from its ele- 

 ments. — JBer. Berl. Ghem. Ges., xxii, 989, May, 1889. G. f. b. 



4. On the identity of Seminose and Mannose. — A short time 

 ago Reiss showed that a constituent of certain seeds, hitherto 

 supposed to be cellulose, afforded on hydrolyzation a sugar, to 

 which he gave the name seminose. Although its hydrazone 

 showed the closest similarity with that of mannose, yet its be- 

 havior with lead acetate led Reiss to regard it as a different 

 sugar. E. Fischer and Hirschberger have re-examined the 

 behavior of mannose with lead acetate and have found that con- 

 trary to their earlier statement, this sugar is precipitated by lead 

 acetate, and therefore agrees in this regard with seminose. The 

 authors have produced mannosoxime by the action of hydroxyl- 

 amine hydrochlorate on mannose, and have found its melting 

 point to be between 176° and 180° ; Reiss having found 176° for 

 the melting point of seminosoxime. So also the not quite pure 



