March 21, 1913] 



SCIENCE 



461 



means of a telescope and scale. The needle was 

 in the magnetic meridian, the two deflecting mag- 

 nets being balanced against each other. The 

 needle was also loaded with a few copper wires, 

 and the earth's field was partially compensated, 

 so that the period of oscillation of the needle was 

 about twenty seconds. When one of the deflecting 

 magnets is then connected with either terminal of 

 an influence machine, the other terminal being 

 grounded, its deflecting effect on the needle was 

 increased. This effect was found to be varied by 

 disturbances of the air in the room due to the 

 movement of an assistant. The observed effect 

 was not appreciably modified by wrapping the 

 magnet in tinfoil. A puff of tobacco smoke over 

 the deflecting magnet also changed the apparent 

 deflecting effect. It gradually became apparent 

 that a change in the permeability of the air was 

 produced, when the magnet was put into contact 

 with the influence machine in an adjoining room. 

 Apparently, the electrified molecules of air ar- 

 -ranged themselves along the lines of the magnetic 

 field, with the planes of rotation of the electrical 

 whirls within the molecules set at right angles to 

 the magnetic lines. The permeability of the air 

 was thus increased, in somewhat the same way 

 that iron filings in the field of the magnet would 

 increase it. 



When the electrified air around the magnet is 

 disturbed by a palm-leaf fan, the permeability of 

 the air is decreased. By proper timing of these 

 disturbing effects of the fan, the amplitude of 

 swing of the needle may be gradually increased to 

 four degrees of arc. By operating the fan during 

 the other semi-vibration of the needle it may be 

 brought quickly to rest. 



Professor Nipher is now seeking to obtain pho- 

 tographs of auroral displays around the poles of 

 a steel magnet. 



George 0. James, 

 Corresponding Secretary 



THE BOTANICAL SOCIETY OP WASHINGTON 



The eighty-sixth regular meeting of the Botan- 

 ical Society was held at the Cosmos Club, Tuesday 

 evening, February 4, 1913. 



The following persons were elected to member- 

 ship: Professor E. Kent Beattie, Dr. Charles 

 Brooks, Mr. J. G. Grossenbacher, Dr. Neil E. 

 Stevens. 



The following program was presented: 



Mr. T. H. Kearney: Indicator Value of Natural 

 Vegetation in the Tooele Valley, Utah. 



This paper outlined the results of an investiga- 

 tion conducted last summer by the Offices of 

 Alkali and Drought Eesistant Plant Investigations 

 and of Biophysical Investigations of the Bureau 

 of Plant Industry. The Tooele Valley lies between 

 the Oquirrh and Stansbury ranges and extends to 

 the south shore of Great Salt Lake. 



It was found that the valley is occupied by 

 some half dozen principal plant associations, each 

 of which is characterized by the presence of one, 

 or, at most, two dominant species of shrubs or 

 perennial herbs. The presence of one or another 

 association was found to be closely indicative of 

 the moisture relations and salt content of the sub- 

 stratum. The areas occupied by the different 

 associations are often so sharply defined as to be 

 recognizable at a distance of several miles. 



The presence of a good stand and growth of 

 sage brush {Artemisia tridentata) is always asso- 

 ciated with a soil of rather light texture, very dry 

 during the summer months, free from alkali salts 

 and with a low water table. This Artemisia asso- 

 ciation occupies mainly the higher lands of the 

 valley. Descending the valley toward the shore 

 of Great Salt Lake, successive zones are traversed 

 which are occupied by the following associations: 

 (2) Koohia vestiia, (3) Atriplex confertifolia 

 (Shadscale), (4) Atriplex confertifolia and Sar- 

 cobatus vermiculatus (Greasewood), (5) Allen- 

 rolfea occidentalis, (6) Distichlis spicata (Salt 

 Grass) and two species of Salicornia. 



Where associations 2 and 3 occur the soil is 

 very dry during the summer, but has a higher 

 moisture capacity than in the Artemisia associa- 

 tion and the subsoil is strongly saline. Under 

 association 4 the soil becomes saline to the surface 

 and the ground water table is relatively high. 

 Associations 5 and & occupy the wet and highly 

 saline soils near the level of the water surface of 

 the lake and are interrupted by bare expanses 

 covered with a crust of salts (chiefly sodium 

 chloride). 



The suitability for crop production of the dif- 

 ferent types of land in this valley can be predicted 

 with much confidence from the character of the 

 native growth. 



Mr. Harry B. Shaw: The Control of Seed Pro- 

 duction in Beets. 



Practically all sugar-beet seed used in the 

 United States is imported. Successful attempts 

 have been made in Utah, Idaho and Washington 

 to produce sugar-beet seed, but in other regions 



