242 Scientific Intelligence. 



together and more compact on the edges. If a rod of aluminum 

 be placed in the boat, a felted but non-elastic mass of carbon is 

 deposited which can be kneaded and can be compressed into a 

 mass like graphite (B). The variety (A) was treated with fuming 

 nitric acid and potassium chlorate for 24 hours at 20° to 25°. A 

 dark chestnut-brown powder remained undissolved, having the 

 composition C^H^Og. Further heating with the oxidizing mixture 

 to 50 c -60°, converted it into a bright brown-yellow powder, 

 C n H 6 6 , burning energetically when heated. Substances essen- 

 tially similar were obtained from (B). It would appear that this 

 carbon is not identical with either of the three varieties exam- 

 ined by Berthelot, although it resembles somewhat his u electric 

 graphite." This latter, however, gives on oxidation a dark brown 

 powder, which leaves on ignition agranular heavy residue ; while 

 the cyanogen carbon gives a bright brownish yellow oxidation 

 product, yielding on ignition a fine light powder. From retort- 

 carbon, however, the authors obtained the bright brownish yellow 

 oxidation product; and they propose for such substances the 

 name " carboxydhydrates. — C. JR., cxi, 774; Per. JBerl. Chem. 

 Ges., xxiv, Ref. 2, January, 1891. g. e. b. 



6. Principles of General Organic Chemistry ; by Prof. E. 

 Hjelt.— Translated by J. Bishop Tingle, Ph.D., F.C.S. 12mo,pp. 

 x, 220. London, 1890. (Longmans). This little volume treats 

 of the philosophy of organic chemistry. Ordinary text-books, 

 devoted to the description of organic compounds, if complete, 

 are encyclopedic ; and the student is apt to lose sight of the 

 philosophy in the mass of the facts. This book is intended to 

 supplement the ordinary manuals. In its first part the compo- 

 sition of organic compounds is considered. In the second, their 

 physical properties. And in the third, their general behavior. 

 The statements made are clear, concise and accurate, and the 

 principles laid down are illustrated by numerous examples. The 

 book is well translated, and its mechanical execution is neat and 

 substantial. 



7. Photographic action of Electromagnetic Waves. — Franz von 

 Dobrzynski claims to have obtained photographic indications of 

 electromagnetic waves in air, employing the method of producing 

 these waves which has been described by Hertz. The plane of 

 the negatives either included the axis of the vibrator or was at 

 right angles to it, and the time of exposure was three hours. 

 The action was visible after development by the appearance of 

 alternating bright and dark bands across the direction of vibra- 

 tion of the waves, or by the appearance of dark bands in the 

 direction of the vibration. The author concludes that waves of 

 from 0*6 to 20 cm. are effective, and promises a further account 

 of his experiments. — Wiener Perichte, Oct. 9, 1890. j. t. 



8. Measurement of Dielectric Constants by means of Herttfs 

 Phenomenon. — E. Lecher has continued the work of J. J. Thom- 

 son on this subject, and has compared the results obtained by the 

 method of electrical oscillations with those obtained by his other 



