472 



SCIENCE. 



[N. S. Vol. XXIII. No. 586. 



Slow drying' will kill a culture that wiU 

 remain in good condition after rapid drying. 



A highly concentrated medium comparable 

 to that which the almost dry cultures must 

 endure will kill the bacteria in question in an 

 exposure of a few days. 



KLVKL F. KJELLEEMAN, 



T. D. Beckwith. 

 BuKEAU OF Plant Industry, 

 Washington, D. C. 



CURRENT NOTES ON METEOROLOGY. 



HELM CLOUDS IN NORTH CAROLINA. 



In the Monthly Weather Review for Oc- 

 tober, 1905, Frank W. Proctor mentions the 

 occurrence of standing clouds in atmospheric 

 waves at "Waynesville, N. 0. (see also Science, 

 May 1, 1903, page Y12). This place is sur- 

 rounded on three sides by high and steep 

 mountains, and the topography is favorable 

 for the formation of such clouds. On the 

 day when the observation was made the wind 

 was southwest, and blew across the mountain 

 range which forms the head of the valley. A 

 large dense standing cloud was formed over 

 the mountains, carried down on the lee side for 

 a short distance, and was seen to evaporate 

 at its leeward edge as fast as it developed to 

 windward. About a quarter or a half a mile 

 to leeward, at the same level approximately, 

 and separated from this main cloud by a clear 

 space, there was a second, detached, standing 

 cloud of good size, also forming to windward 

 and evaporating to leeward like the primary 

 cloud. The wind at the level of the clouds 

 was blowing at the rate of twenty miles an 

 hour, yet the clouds were stationary, dissolving 

 as rapidly at one side (lee) as they formed at 

 the other (windward). Mr. Proctor's account 

 of these helm clouds in the mountains of 

 North Carolina is the second mention of this 

 phenomenon. The first was made by Pro- 

 fessor W. M. Davis {Bull. Geogr. Soc. Phila., 

 III., No. 3, 1903). 



daily march of temperature in the tropics. 

 Hann has undertaken an extended investi- 

 gation of the daily march of temperature in 

 the tropics, the first part of which has been 

 published (' Der tagliche Gang der Tempera- 



tur in der inneren Tropenzone,' Denkschr. k. 

 Akad. Wiss., math.-naturw. Kl., "Vienna, 1905, 

 Vol. LXXVIII.). The reason for taking up 

 this study is found in the fact that the mean 

 temperatures of many stations in the tropics 

 are placed too high because of the application 

 of inaccurate corrections in computing the 

 true means. The present work is to be re- 

 garded as an extension of that of Dove, pub- 

 lished in 1846 and in 1856 (' Ueber die tiig- 

 lichen Veranderungen der Temperatur der 

 Atmosphare,' Ahhandl. Berl. Akad.), and in- 

 cludes the latest available observations from 

 stations between the equator and latitudes 

 ±15° N. and S., in Africa, the West Indies, 

 Central and South America, southern Asia, 

 northern Australia and the tropical oceans. 



rainfall op MEXICO. 



A report on the 'Eegimen of the Rainfall 

 of Mexico,' in the twelfth volume of the 

 Annals of the Association of Engineers and 

 Architects of Mexico, by Romulo Escobar, 

 brings to light an interesting fact. Most of 

 the stations show a steady diminution in rain- 

 fall for a long period of years, but this de- 

 crease has already begun to be followed by 

 an increase. Our gulf states from Texas to 

 Alabama and Tennessee have shown a similar 

 decrease, but the expectable increase has not 

 been observed everywhere, owing, as Professor 

 Abbe believes, to the frequent changes in the 

 rain gauges and their exposures. It is to be 

 noted with satisfaction that in this report on 

 Mexican rainfall there is no indiscriminate 

 comparison of a long record at one station 

 with a short record at another, the rainfalls 

 being averaged for each station by lustra, so 

 that mean annual rainfalls for the same period 

 may be compared (Mo. Wea. Rev., Oct., 1905). 



NOTES. 



According to a list recently published in 

 Peiermann's Mittheilungen (1905, p. 91) it 

 appears that out of forty-four universities 

 and technical schools iising the German lan- 

 guage, thirteen recognized meteorology as 

 worthy of special mention in their couraes of 

 instruction offered during the past summer 

 semester. 



