Chemistry and Physics. 321 



the Royal Institution of Great Britain, by Dr. Allan Macfadyen, 

 Director of the Jenner Institute of Preventive Medicine, it is 

 stated that there is little or no evidence that electricity has a 

 direct effect upon bacterial life. The effects produced appear to 

 be of an indirect character, due to the development of heat or to 

 the products of electrolysis. — Nature, p. 359, Feb. 7, 1901. 



J. T. 



11. Electric Convection. — M. V. Cremieu has repeated his 

 original experiments with additional precautions, and believes 

 that under the conditions of the experiments of Rowland and 

 Himstedt, electric convection produces no magnetic effect. — 

 Comptes Pendus, Feb. 11, 1901. j. t. 



12. Preservation of Photographic Records. — Dr. W. J. S. 

 Lookyer has called attention to the disappearance of feeble 

 photographic impressions during the lapse of time, and speaks of 

 various methods of intensification. Mr. Chapman Jones discusses 

 the subject and shows that the photographic film should consist 

 of pure silver in clean gelatine. Ammonia, ferrous oxalate, and 

 potassium cyanide should not be used. Long w r ashing is insisted 

 upon. Acid fixing baths should not be used. The exposed pho- 

 tographic image should be protected from the air. Prints should 

 be taken from the negatives as soon as possible : for deteriora- 

 tion probably goes on even if the above precautions are taken. — 

 Nature, p. 373, Feb. 14, 1901. j. t. 



13. The Eclipse Cyclone and the Diurnal Cyclone. The latest 

 publication of the Annals of the Astronomical Observatory of Har- 

 vard College (Vol. xliii, Part I) contains an interesting paper by 

 Prof. II. Helm Clayton on the cyclonic disturbance produced at 

 the time of the total eclipse of May 8th, 1900, as the result of the 

 accompanying fall of air temperature. The circulation of the wind, 

 blowing spirally outward from the center, and the form of the 

 pressure-curve accompanying it, correspond closely to the type of 

 cold-air cyclone developed by Ferrel. Special interest attaches 

 to this eclipse cyclone because of the simplicity of the phenomena 

 with which it is connected, the complication due to vapor conden- 

 sation or conflicting air currents present in the ordinary cyclone 

 being here entirely absent. The results show that a lall of tem- 

 perature of a few degrees is capable of developing a typical cold- 

 air cyclone in a wonderfully short time. Further, the eclipse cyclone 

 showed no apparent lag due to the inertia of the air, but moved 

 on continuously with the eclipse shadow at the rate of some two 

 thousand miles an hour, being dissipated almost instantly in its 

 rear. Hence the motion has a certain analogy to wave-motion, a 

 given particle of air not moving more than five miles as a maxi- 

 mum during the passage of the eclipse. 



In the light of this investigation, the author goes on to show 

 that the double diurnal period long noted in the atmospheric 

 pressure, is probably due to independent diurnal cyclones of the 

 two types recognized by Ferrel, one developed by the cold of 

 night and the other by the heat of day. This theory when closely 



