40 



NATURE 



[Septemb'er 12, 191: 



current required in the ring is 100 million amperes. 

 The magnetic field due to this current at the 

 earth's surface is given as 68 ly, which represents 

 a magnetic storm of the first order. 



In considering how the question is affected by 

 the presence of the earth's atmosphere, Stormer 

 inclines to the views of Wegener (while not com- 

 mitting himself to the existence of a gas, "geo- 

 coronium," of one-fifth the density of hydrogen). 

 At altitudes above 100 kilometres there is supposed 

 to be no trace of anything but the lighter gases, 

 especially hydrogen (and geocoronium, if it exists). 

 In agreement with Lenard, Stormer concludes that 

 ordinary kathode rays coming from space would 

 be absorbed in the upper hydrogen atmosphere 

 before reaching the 100 kilometres level, that 

 /3-rays of radium would be absorbed in the nitrogen 

 atmosphere at heights of 50 to 70 kilometres — a 

 common altitude for the lower border of auroral 

 " curtains " — and that the rays forming the lowest 

 aurora he has measured must have a greater pene- 

 tration than /3-rays. Fairly substantial evidence 

 has been advanced by Paulsen and others that 

 auroras in the auroral belt, especially in Green- 

 land, sometimes come much below the lowest 

 height, 36 kilometres, observed by Stormer at 

 Bossekop. This tends to support Birkeland's 

 latest views as to an enormously high velocity in 

 the rays if they originate in the sun. On the 

 other hand, there seems reason to accept Stormer's 

 view that auroras seen in low latitudes are usually 

 at considerably greater heights than those seen in 

 the Arctic. Thus aurora in low latitudes would 

 seem to arise from rays of less, not of higher, 

 penetration than those in high latitudes, which 

 seems inconsistent with Birkeland's hypothesis. 



Stormer's mathematical work, like Birkeland's, 

 assumes the motion of the individual corpuscle to 

 be unaffected by the presence of other corpuscles. 

 This is one of the principal criticisms urged by 

 Prof. Schuster,- who concluded that the scattering 

 inevitably produced is fatal to Birkeland's theory, 

 so far at least as magnetic storms are concerned. 

 The same criticism would seem to apply, with at 

 least equal force, to Stormer's theory. It would 

 thus be of great interest to have Prof. StSrmer's 

 views on the validity of Prof. Schuster's criticisms. 

 Meantime, considering the calibre of the pro- 

 tagonists, the prudent course seems to be to "wait 

 and see." But whatever the fate of St5rmer'-s 

 theoretical work may be, his photographs of 

 aurora clearly constitute a fundamental advance 

 towards exact knowledge. In temperate and 

 southern Europe, aurora and large magnetic 

 storms are both rare events, and their coincidence 

 of occurrence seems the rule rather than the excep- 

 tion. A total absence of physical connection 

 between the two phenomena seems thus almost 

 inconceivable. The careful intercomparison of 

 measurements of aurora — rendered possible by 

 Stormer's work — with contemporaneous records 

 from magnetic observatories is clearly one of the 

 most promising methods of getting at the root of 

 the matter. " C. Chree. 



"- Roy. Soc 



::., A. 85. 



FROF. THOMAS WINTER. 



PROF. THOMAS WINTER, of the University 

 College of North Wales, Bangor, whose 

 death we recorded in our last issue, was the son 

 of Mr. Thomas Winter, of Lotherton Park, 

 Aberford, Leeds. Born in 1866, he was educated 

 at the Darlington Grammar School under Dr. 

 Wood, and afterwards proceeded to the University 

 of Edinburgh, where in 1888 he graduated in arts 

 with honours in natural science. On leaving the 

 University he became a master at a Scarborough 

 school, and later at the Norfolk County School at 

 Dereham. The son of a successful practical farmer, 

 and equipped with a university training in natural 

 science, he was naturally attracted to the develop- 

 ment of schools of agriculture in the provincial 

 colleges and universities which marked the later 

 decades of the last century. In iSgi he was 

 appointed assistant lecturer in agriculture at the 

 University College of North Wales, Bangor. In 

 1892 he accepted a similar appointment at the 

 Yorkshire College, Leeds, as it then was, but 

 returned in 1894 to Bangor as head of the depart- 

 ment of agriculture, a post which he occupied 

 for the next eighteen years. It is thus in North 

 Wales that his life-work chiefly lay, and 

 where the stimulus which he gave to the cause of 

 agricultural education will be longest felt. 



The work of a school of agriculture has its 

 internal and external sides. On the internal side 

 courses of instruction have to be provided with 

 a view to certificates, diplomas, and degrees. On 

 the external side the agricultural community 

 within the area served by the school has to be 

 considered, and extension lectures, field experi- 

 ments, and instruction in dairy-work have to be 

 provided for the benefit of those who cannot reach 

 the college. In both these aspects of the work 

 of his chair. Prof. Winter achieved a rare 

 success. Within the University of Wales his 

 sound judgment contributed to the framing of the 

 existing scheme of instruction for the degree in 

 agriculture and rural economy, the marked 

 feature of which is the requisition of an adequate 

 acquaintance with the pure sciences, prior to the 

 study of their applications to agriculture. It was 

 also to Prof. Winter's fostering care that the c^air 

 of forestry was established at Bangor. 



In • the ' external work of the department 

 his gift, of .organisation and. his tact and- good 

 sense have greatly contributed to the removal 

 of the distrust of agricultural education among 

 old-fashioned, farmers. Not the least contribu- 

 tion to this end was his successful management 

 of a college farm, where experiments in cropping 

 and breeding have been carried out, and where 

 the visits of farmers and their sons and daughters 

 have always been welcomed. Prof. Winter's death 

 while still in the prime of life will be greatly 

 deplored by his colleagues on the senates of his 

 college and university, by his former pupils 

 scattered in many parts of the world, and not 

 least among the' farmers of the North \\'elsh 

 counties. 



NO. 2237, VOL. 90] 



