424 



NATURE 



[June 3, 1920 



The values are smoothed up to 1900, but not in later 

 years. 



I have placed an asterisk in the table and diagram 

 to those years in which a conjunction occurred 

 between the red spot and the south tropical spot. In 

 every case it will be seen that the red spot moved at 

 a more rapid rate in those years when conjunctions 

 were observed. 



The south tropical spot or disturbance is a totally 

 different object both in form and nature, and probably 

 in origin, from the great red spot. The latter has pre- 

 served its symmetrical oval form since it was ob- 

 served by Dawes in 1857, but the former has varied 

 enormously in its length and detail. In 190 1 it was 

 scarcely more than 20° long, in 1902 July 87°, in 

 1903 48°, in 1905 44° to 60°, in 191 1 115°, in 

 1912 65°, in 1913 March 140°, and in 1918 180°, so 

 that in the last-mentioned year it extended half-way 

 round the vast diameter of Jupiter. 



This marking exhibited undue faintness in 19 18 

 and the early part of 19 19, and it appeared to be on 

 the eve of disappearing, like the hollow in the great 

 south equatorial belt where the red spot lies. How- 



Phillips and Mr. F, Sargent, and I take this oppor- 

 tunity of acknowledging their kindness in furnishing 

 the necessary materials. My abstention from 

 planetary work has been practically enforced, but, 

 amid the regret caused thereby, I feel great satisfac- 

 tion in the fact that others are pursuing it with much 

 ability and energy. W. F. Denning. 



Bristol, May 11. 



Fig. I. — Rates of rotation of the Great Red Spot on Jupiter 



ever, there has recently been some intensification in 

 the material forming the south tropical spot, so that 

 observations are being made to trace its position and 

 developments. It is satisfactory also to know that 

 the red spot itself continues to retain its definite 

 form, and is sufficiently distinct to be within easy 

 recognition when a steady air conduces to good seeing. 

 This spot seemed to be breaking up or wearing out 

 early in 1919, but it has recovered something of its 

 old-time aspect, and is well within reach of the tele- 

 scopes usually in the hands of amateurs. 



Since Schwabe first saw the hollow on the south 

 side of the great south equatorial belt of Jupiter in 

 183 1 September 5, the planet has rotated more than 

 78,000 times. There is every reason to conclude that 

 the object he saw is the same as that which has 

 been so prominently visible in recent years in close 

 contiguity to the red spot. The two features appear 

 to have participated in one and the same fluctuating 

 rate of rotation, a mean of which was 9h. 55m. 36-8s. 

 during the 88| years included in the observations. 



The observations upon which my deductions for 

 recent years are based were made by the Rev. T. E. R. 

 NO. 2640, VOL. 105] 



British and Foreign Scientific Apparatus. 



Now that we are living in an age of " trusts " 

 there is no need to fear foreign competition in 

 respect to prices. The only points our home manu- 

 facturers should lay stress upon are quality and 

 quantity, and should these be maintained at a high 

 level they can hold their ground against foreign manu- 

 facturers ; that is, so long as the manufacturers 

 throughout the world have confidence in their respec- 

 tive associations. Whenever these commercial asso- 

 ciations begin to fall asunder we may expect com- 

 petition in prices to operate, and then it will mean 

 a commercial war, not between nations, but between 

 individual manufacturers in Europe 

 and America. The result will mean 

 financial benefit to the users of 

 scientific apparatus, just as the 

 recent slump in prices of the neces- 

 saries of life may soon prove to be 

 advantageous to consumers generally 

 throughout the world. 



Scientific apparatus is as neces- 

 sary to the maintenance of healthy 

 life as are hygenic clothing and 

 wholesome food; and if protection 

 f6r British manufacturers is required 

 in the form of prohibition except 

 under licence to induce them to im- 

 prove the quality and the output, 

 with the ultimate object of develop- 

 ing an optical industry within the 

 Empire of such importance that 

 there would be less danger to the 

 State in the event of another war, 

 why should the users of scientific 

 apparatus be expected to bear the 

 hardships in regard to poorer quality 

 and higher prices even for a tem- 

 porary period? Surely it is a ques- 

 tion for the Government to decide 

 as to what amount of State aid is 

 required to develop a key industry that the whole 

 nation may be called upon to bear the expense instead 

 of an extremely small minority of the population. 



In pre-war days our principal foreign competitor 

 was Germany, not so much in price as in quality, 

 and if German manufacturers were able to develop 

 an industry of very considerable importance without 

 State aid, why cannot British manufacturers do 

 likewise? 



There was one person in Germany who was more 

 responsible than all other makers together in lowering 

 prices, viz. Leitz of Wetzlar. He always appeared 

 satisfied with a comparatively small profit, and aimed 

 at a very large output ; and, I believe, he was the first 

 to sell i/i2-in. oil immersion objectives at 5L, and 

 curiously this ultimately became a uniform price 

 throughout the trade in Europe and America. The 

 same maker sold students' microscope stands at 55s., 

 which, with suitable optical equipment, was a service- 

 able instrument with highest magnifications. The 

 prices of these articles to-day are 9I. and 8L 55. — 

 higher than the British equivalents. 



Since the armistice German manufacturers have 



