390 



NATURE 



[February 23, 1905 



as mapped permits ready adjustment of the observed quan- 

 tities for closed areas, in accordance with the potential 

 hypothesis, and it may even permit, to a certain degree, the 

 testing of the accuracy of this assumption, though as 

 regards the latter more can be said at the end of a year's 

 work. 



While it is not anticipated that any marked irregularities 

 in the distribution of the earth's magnetism will manifest 

 themselves over the deep waters of the Pacific, it may con- 

 fidently be expected that in the neighbourhood of the islands 

 and along the coasts distortions and irregularities will be 

 revealed. With the aid of the results of the detailed mag- 

 netic survey of the United States and Alaska, opportunity 

 will therefore be afforded of studying the effect of the 

 configuration of land and water upon the distribution of 

 the magnetic forces. The first circuit, passing as it does 

 along the American and Asiatic coasts, will yield especially 

 interesting results in this respect. Thus, for e.xample, along 

 the Aleutian Islands marked local disturbances will be 

 disclosed. Reports are received frequently from mariners 

 in this region regarding the unsatisfactory behaviour of the 

 compass ; it is therefore greatly to be desired that a sys- 

 tematic magnetic survey of the waters in this region be 

 made. 



L. A. Bauer. 



Department of Terrestrial Magnetism. 



Carnegie Institution, Washington, D.C. 



Recently Observed Satellites. 



Is reply to Sir Oliver Lodge's letter in Nature of 

 January 26 (p. 295), it may be said that while it is perfectly 

 possible that the newly discovered satellites are captured 

 comets (see Harvard Annals, liii., p. 60), yet the chances 

 against the actual occurrence of the required conditions at 

 exactly the right times, even in one case, are exceedingly 

 large ; in two cases they are practically prohibitive. 



With regard to a possible meteoric constitution, it is 

 known that the density of the four larger satellites of 

 Jupiter is extremely small — but little above that of water. 

 That their discs are frequently found to be elliptical when 

 seen under favourable conditions has now been noted by more 

 than a dozen different astronomers. The regularly recur- 

 ring changes in their ellipticity, noted by several observers, 

 taken in connection with the small density of these bodies, 

 can hardly be explained in any other manner than by a 

 meteoric constitution. Such being the case, it is highly 

 probable, as Sir Oliver Lodge suggests, that the newly 

 discovered satellites are similarly constituted. 



A reply to his further suggestion that they are now in 

 process of dissolution is impossible in the present state of 

 our knowledge. If formed according to the nebular hypo- 

 thesis, however, as seems most probable, and if they have 

 accordingly existed through the ^ons during which their 

 primaries have been contracting to their present dimen- 

 sions, it seems highly unlikely that they should not yet 

 have reached a permanent condition. 



William H. Pickering. 



Cambridge, Mass., U.S. .A., February 9. 



Compulsory Greek at Cambridge. 



The proposals of the Studies and Examinations Syndicate 

 in regard to certain changes in the Previous Examination 

 are to be submitted to the Senate on' March 3 and 4. 

 Members of the Senate may record their votes on either of 

 these days between 1 and 3, or between 5 and 7 p.m. The 

 controversy has chiefly turned on the proposal to abolish 

 compulsory Greek, and it is mainly on this question that 

 the issue will be decided. 



h\\ the five Graces are important, but Grace II., which 

 raises the main issue, is the most important of all. 



The secretaries of the committee in support of the recom- 

 mendations of the syndicate will be glad to hear from 

 non-resident members of the Senate who have not already 

 intimated their intention of supporting the proposed reform. 

 It is believed that amongst resident members of the Senate 

 a majority will vote in favour of I he new scheme, but 



NO. 1843, VOL. 71I 



the decision is largely in the hands of non-resident voters. 

 As it is proposed to issue a final list of supporters shortly 

 before March 3, it will be a convenience if additional names 

 are sent to Mr. A. C. Seward, Emmanuel College, Cam- 

 bridge, at once. 



R. Vere Lauren'Ce, 

 H. Rackham, 

 k. C. Seward. 

 Cambridge, February 21. 



The experiences of Mr. Willis and others suggest that 

 mine may be in point. Mr. Willis was behind in classics. 

 He wasted 1052 hours on Greek and passed. His present 

 knowledge of Greek, he adds, is nil. 



Mathematics were my difficulty. Being destined for 

 Cambridge, I was specially coached in mathematics at 

 school. .Arrived here I was again coached, but failed. 

 Coached once more I passed, having wasted, not one, but 

 several hundred hours on that study. Needless to say, my 

 knowledge of mathematics is nil. 



My case is that of hundreds. Why, then, are not com- 

 pulsory mathematics to be reformed away? Because they 

 can be used in trades and professions for the making of 

 money. But the things that put one touch of art in the 

 life of a dull boy, that open his eyes for once to another 

 %vorld, where " utility " does not count — they, forsooth, 

 must be dispensed with because in the market they have no 

 value. And, verily, they are without price. 



.Away from Cambridge, an intelligent lady was lately 

 speaking to me of her nephew at the University of Birming- 

 ham. Knowing nothing of our pending " reform," she 

 said : " He is going to be an engineer. But he has got to 

 waste his time passing in French, and German, and 

 English. He will never want them again in his whole 

 course. It is absurd." W. Bateson. 



Cambridge, February 17. 



Secondary Radiation. 



In a paper recently published (Transactions Royal 

 Dublin Society and Phil. Mag., February) I described some 

 work on secondary & radiation given off by substances when 

 exposed to /3 (and 7) rays from radium. The paper gave the 

 relative intensity of this secondary radiation for only a few 

 elements, but the results from these few indicated that the 

 greater the atomic weight the greater was the secondary 

 radiation. 



I have since tested a large number of elements, and found 

 this rule to hold without a single exception. The list of 

 substances tested was a very varied one, including carbon, 

 magnesium, aluminium, chromium, iron, nickel, copper, 

 zinc, arsenic, selenium, molybdenum, silver, tin, antimony, 

 tungsten, platinum, mercury, lead, and bismuth. 



The secondary radiation is not proportional to the atomic 

 weight ; it increases less rapidly than the atomic weight. 



This very general result appears to be of interest as bear- 

 ing on the subject of radio-activity and atomic structure in 

 general, but cannot be further discussed here. 



J. -A. McClelland. 



University College, Dublin, February 13. 



Tenacity to Life of a Grass-snake. 



.A grass-snake which the writer had in his possession 

 for eighteen months has just died. 



.A fact which seems worthy of note is the length of 

 time during which this snake fasted. The last time 

 the snake fed was June 11, 1904, the meal consisting of 

 a small frog. From that time until the date of its death, 

 February 2, it took no food, although constantly offered 

 it. The animal thus existed for close on eieht months with- 

 out food. During the whole of this time it appeared in good 

 health, and was, at times, most animated. No approach to 

 liibernation was observed, and only for a little more than a 

 week before its death did the snake seem out of health. The 

 bodv was not unduly thin. E. V. Windsor. 



Barnet, February 7. 



