Chemistry and Physics. 87 



hydrocarbons is much greater than with hydrogeD. No satis- 

 factory explanation is given for the curious fact that combustion 

 does not take place at all until sufficient oxygen is present for 

 the complete combustion of the hydrocarbon. — Zeitschr. physical. 

 Chem., xxxv, 340. h. l. w. 



4. The Combustion of Acetylene in Air enriched with Oxygen. 

 — Having occasion to use high temperatures, G. L. Bourgerel 

 experimented with acetylene by using it in an ordinary blast- 

 lamp. This gave a very high temperature by means of which 

 nickel or pure gold could be melted with ease. Still higher tem- 

 peratures being desired, the air used for the lamp was replaced 

 by pure compressed oxygen from a cylinder. The result was sur- 

 prising from the fact that the flame leaving the blowpipe was 

 exceedingly brilliant. The gases did not mix, but burned only 

 in contact with one another, then, little by little, there formed at 

 the extremity of the central tube of the blowpipe a deposit of 

 carbon which rapidly increased, taking the form of a truncated 

 cone with the base outward. The carbon thus formed was very 

 dense and that at the base of the flame was hard and sonorous, 

 and in some instances sufficiently hard to scratch glass. When 

 examined with a lens the carbon showed a cauliflower-like struc- 

 ture. The curious phenomenon was evidently due to the disso- 

 ciation of acetylene. As the incomplete combustion when pure 

 oxygen was used was unsatisfactory for the purpose of heating, 

 mixtures of oxygen with air were tried with the result that very 

 hot oxidizing or reducing flames could be produced. — Moniteur 

 Scientifique ;■ Chem. News, lxxxii, 187. h. l. w. 



5. The inverse effect of a magnetic field upon an electric 

 charge. — M. G. Lippman, reasoning upon Maxwell's theory of 

 electric convection, shows by the principle of the conservation of 

 energy that variations in the strength of a magnetic field ought 

 to produce a movement of an electrified body placed in such a 

 field. M. V. Cremieu has put this conclusion to the test of experi- 

 ment. A charged aluminum disc is supported between the poles 

 of an electro-magnet. The author calculates how much turn- 

 ing eflect he should obtain on closing or breaking the circuit of 

 the magnet. He did not obtain any effect, and he concludes 

 therefore that this experiment taken in connection with his pre- 

 vious one on electrical convection (Comptes Rendus, cxxx, p. 

 1544, 1900) proves that the displacement of an electrified body 

 does not produce a magnetic field along its trajectory. — Comptes 

 Rendus. No. 15, p. 578, Oct. 8, 1900. J. t. 



6. Electrical Convection. — M. V. Cremieu returns to his attack 

 on the experiments relating to the possibility of this effect. He 

 has repeated those of Rowland and Himstet, and shows apparently 

 that the effects observed are not due to the magnetic effect of 

 moving charges, since they can be suppressed by the intervention 

 of a metallic plate. — Comptes Rendus, Nov. 12, 1900. J. t. 



V. Unipolar Induction. — E. Lecher continues his discussion 

 with W. Konig on the question whether a magnetic pole can 



