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SCIENCE 



[N. S. Vol. XXX. No. 766 



recent experiments of Geiger, however, 

 show that the scattering of the a particles 

 is very marked, and is so great that a 

 small fraction of the a particles, which im- 

 pinge on a screen of metal, have their ve- 

 locity reversed in direction and emerge 

 again on the same side. This scattering 

 can be most conveniently studied by the 

 method of scintillations. It can be shown 

 that the deflection of the a particle from 

 its path is quite perceptible after passing 

 through very few atoms of matter. The 

 conclusion is unavoidable that the atom is 

 the seat of an intense electric field, for 

 otherwise it would be impossible to change 

 the direction of the particle in passing over 

 such a minute distance as the diameter of 

 a molecule. 



In conclusion, I should like to emphasize 

 the simplicity and directness of the meth- 

 ods of attack on atomic problems opened 

 up by recent discoveries. As we have seen, 

 not only is it a simple matter, for example, 

 to count the number of a particles by the 

 scintillations produced on a zinc sulphide 

 screen, but it is possible to examine directly 

 the deflection of an individual particle in 

 passing through a magnetic or electric 

 field, and to determine the deviation of 

 each particle from a rectilinear path due 

 to encounters with molecules of matter. 

 We can determine directly the mass of 

 each a particle, its charge, and its velocity, 

 and can deduce at once the number of 

 atoms present in a given weight of any 

 known kind of matter. In the light of 

 these and similar direct deductions, based 

 on a minimum amount of assumption, the 

 physicists have, I think, some justification 

 for their faith that they are building on 

 the solid rock of fact, and not, as we are 

 often so solemnly warned by some of our 

 scientific brethren, on the shifting sands of 

 imaginative hypothesis. 



E. RUTHEEFORD 



TBE HIGHEST BALLOON ASCENSION IN 



AMERICA 

 Although a large number of hallons-sondes 

 were despatched from St. Louis in 1904-7 

 under the direction of the writer (see Science, 

 Vol. 27, p. 315), none had been employed in 

 the eastern states until last year. In May and 

 July, 1908, four ballons-sondes were launched 

 from Pittsfield, Mass., with special precautions 

 to limit the time they remained in the air and 

 so prevent them from drifting out to sea with 

 the upper westerly wind. Three of the regis- 

 tering instruments have been returned to the 

 Blue HiU Observatory with good records. The 

 first instrument sent up on May 7 was not 

 found for ten months and the record, forming 

 the subject of the present article, is very in- 

 teresting because it gives complete tempera- 

 ture data from the ground up to 17,700 

 meters, or 11 miles. This is 650 meters higher 

 than the highest ascension from St. Louis, 

 which, by a coincidence, was also the first one 

 to be made there. On May 7 a general storm 

 prevailed, so that the balloon, traveling from 

 the east, was soon lost in the cloud and its 

 subsequent drift could not be followed, but the 

 resultant course was 59 miles from the south- 

 west, as determined by the place where the in- 

 strument fell two hours later. At the ground 

 the temperature was 4°.5 C, and this de- 

 creased as the balloon rose to the base 

 of the cloud, which itself was considerably 

 warmer than the underlying air. Above 

 the cloud the temperature continued to 

 fall with increasing rapidity up to a height 

 of 12,500 meters (nearly eight miles) where 

 the minimum of — 54:°.5 C. was registered. 

 Here the great warm stratum was entered 

 and penetrated farther than ever before in 

 this country, namely, to the height of 17,700 

 meters, where the temperature was — 46°.5 

 C. An increase of 8°.9 occurred, however, in 

 the first 3,000 meters, for above 15,500 meters 

 nearly isothermal conditions prevailed, con- 

 firming the belief of Teisserenc de Bort that 

 what he calls the ".stratosphere " is composed 

 of a lower inverting layer with isothermal con- 

 ditions above extending to an unknown height. 

 In an ascension last November in Belgium the 



