484 



SCIENCE 



[N. S. Vol. L. No. 1299 



back to the arid portions of the southern 

 Great Plains.^ Observations of forest-fire 

 smoke also give reliable information of air 

 movements over long distances, as in October, 

 1918, when Minnesota smoke was observed 

 throughout the eastern half of the United 

 States except along the gulf and south At- 

 lantic coasts.^ Observations on clouds may be 

 complementary to those on pilot balloons, for 

 the usefulness of pilot balloons decreases as 

 the cloudiness increases. How cloud move- 

 ments may be used in local weather forecast- 

 ing has been discussed by A. H. Palmer for 

 San Francisco, M. L. Fuller for Peoria, HI., 

 and H. H. Martin for Columbus, 0.^ 



AIRPLANES AND THE WEATHER 



An article on the "Effect of vsdnds and 

 other weather conditions on the flight of air- 

 planes "" is a rather extensive, though by no 

 means complete, compilation and discussion 

 of aviators' meteorological experiences. To 

 quote from the synopsis: 



The disturbances of the air due to daytime con- 

 vection are one of the prime sources of bumpiness. 

 Especially on hot summer days do strong, rapidly 

 rising currents of air penetrate to great altitudes 

 and, where encountered, jolt the airplane. 

 "Where the cooler air is descending, the effect is 

 similar to that of falling into a "hole." The 

 height to which the effects of surface roughness 

 extend when the wind is blowing depends upon the 

 speed of the surface wind and the height of the 

 obstruction. 



In the free air, aviators ' observations show how 

 the layers of air flow over one another, the inter- 

 face sometimes being marked by clouds and some- 

 times entirely invisible. At such levels are en- 

 countered bUlows or waves, and considerable 

 difficulty is sometimes experienced in flying 



3 See Winchell and Miller, Mo. Weather Bev., 

 November, 1918, Vol. 46, pp. 502-506. 



i Mo. Weatlier Bev., November, 1918, pp. 506- 

 509. 



^Mo. Weatlier Bev., September, 1918, pp. 407- 

 413; July, 1919, pp. 473-474, and August, 1919, 

 pp. 567-570. A limited supply of separates is held 

 by each of the authors named: address, "Weather 

 Bureau Office" at cities named. 



6 Mo. Weatlier Bev., August, 1919, pp. 523-532, 

 10 figs. 



through such regions. Clouds, rain and fog all 

 contribute to the discomfort and danger of flying. 

 Perhaps the most interesting are the experiences 

 in the thunderstorms and the up-and-down winds 

 which accompany such storms. As the driving 

 wedge of cold air at the surface advances ahead 

 of the storm, the air into which the storm is mov- 

 ing is forced upward. The maximum turbulence is 

 found in the region of the squall cloud, but the 

 force of the rising air ahead of the storm is suffi- 

 cient to carry up an airplane considerably, in, spite 

 of the efforts of the pilots to keep the nose of the 

 plane down. The dangers from lightning and haU, 

 are also quite as important as those from the 

 capricious winds. 



There is an annotated bibliography at the 

 end. This article bound with two on balloon- 

 ing and with reviews of Y. Henderson's 

 " Physiology of the aviator," and H. Lueke- 

 ish's " High lights of air travel," may be had 

 on application to the Chief, U. S. Weather 

 Bureau. 



Charles F. Brooks 



SPECIAL ARTICLES 



A PRELIMINARY NOTE ON FOOT-ROT OF 

 CEREALS IN THE NORTHWEST 



During the first half of May, 1918, the 

 Station Entomologist was called to Olympia, 

 Wash., to consult with the farmers and county 

 agent concerning an outbreak of aphis on 

 wheat. He found that the aphids were not 

 responsible for the whole trouble and sub- 

 mitted samples of wheat from the unthrifty 

 fields to the station plant pathologist for diag- 

 nosis. Subsequently specimens showing the 

 same disease were submitted from this and 

 other localities in western Washington through 

 the county agents of the respective counties. 



Among the first lot of plants were some 

 showing lesions at the base of the stem. 

 These lesions were elliptical, light-centered, 

 penetrating the leaf-sheath and the surface of 

 the stem. Plants with these lesions and others 

 with a general blackening of the lower nodes 

 showed death of the roots at the first node, 

 the plant attempting to make good this loss by 

 putting out roots at the second node. In some 

 plants two sets of roots had been successively 

 killed and roots had been put out at the third 



