( % mistry and Phyti 



in Btrong hydroohlorio aoid with evolution ^i' chlorine. It' daring 

 the heating the superficial layer be continually pressed into the 

 fused mass, t lie composition oi the crystals approaches the for- 

 mula BaCoO r At a higher temperature large iridescent black 

 prisms are obtained, having very closely the composition BaCoO,, 



but containing a trace o( barium platmate. The temperature of 

 their formation is between L 000° and 1100°. — C. A'., oix, 64; J. 

 Chi s ., lvi, 1 11.-), Dee., 1889. <.. v. B. 



5. On tin Constitution of Dextrose. — Skraup has made experi- 

 ments on the pentabenzoyl derivative of dextrose and has afforded 

 evidence that the view oi' Fittig and of Tollens that this sugar 

 may he considered as an ether derived from a heptadiydric 

 alcohol, and therefore as having the formula 



O 

 / \ 



OHCH,[CHOH],CH.CH.OH, 



is correct. The above dextrose derivative is not oxidized by per- 

 manganate to pentabenzoyl gluconic acid; and on treatment with 

 phenyl-hydrazine, two dextrose compounds result, one derived 

 from C,H lt O„ the other from C 6 H 12 6 . H o 0.— J. Chem. Soc, lvi, 

 1130, Dec, 1889. (i. f. b. 



6. Electrical Undulations. — MM. Edouard Sarasin and Lu- 

 cien db la Rive in repeating Hertz's work upon this subject have 

 discovered that the oscillatory character of the electrical charge 

 on a wire submitted to induction, instead of being invariable in 

 character like the vibrations of an elastic column submitted to 

 motions of a definite period, depend, on the contrary, upon the 

 resonator employed by Hertz to explore the wire. The phe- 

 nomena observed by the above mentioned authors is termed mul- 

 tiple resonance. Cornu, on the occasion of the presentation of 

 the communication of the authors of the results of their experi- 

 ments to the French Academy, remarked in substance as folloAvs. 

 The theory of Hertz depends upon two distinct elements: 



(1.) The hypothesis that the spark from a Ruhmkorff coil pro- 

 duces an oscillation of a fixed period, determined by the construc- 

 tion of the exciter. 



(2.) Upon the observation of an apparent periodicity in the 

 electrical state of the wire submitted to electrical oscillations. 

 The experiments of MM. Sarasin and de la Rive throw <*reat 

 doubt upon Hertz's work. Since in the expression A = VT in 

 which A = wave-length, V = velocity of propagation of induc- 

 tion in the wire under examination, T = period of oscillation of 

 the exciter, it is shown that either T is not fixed which is con- 

 trary to the fundamental hypothesis, or that V varies with the 

 exploring apparatus, which is absurd, since V should represent 

 the velocity of propagation of induction, a specific constant. — 

 Comptes Rendu*, Jan. 13, 1890, p. 72. j. r. 



7. Experiment* with Hertz 1 * Vibrations, — Professor G. F. Fitz- 

 gerald states that on connecting a delicate galvanometer with a 

 Hertz resonating receiver, every time a spark passed the galvano- 



