348 



NATURE 



[March 4, 1875 



requiring for their due execution scientific and refined processes 

 and the superintendence of scientific men of high qualifications, 

 are yet, properly speaking, rather applications of scientific views 

 and acquired skill to particular objects of national importance, 

 than undertakings of research having in view as their primary 

 object the advancement of science itself. It is true, that as 

 practice makes perfect, science does gain by such applications, 

 and that by going somewhat out of the way in their execu- 

 tion, and seizing opportunities, most valuable theoretical results 

 and data are occasionally elicited at an additional cost incom- 

 parably less than would be incurred by instituting operations for 

 the purpose ab initio. But when I consider the pregnant nature 

 of scientific truth, and how upon occasion of every well-grounded 

 accession to, or extension of, theoretical knowledge, a new 

 /ra<r//« has arisen founded thereon, and old methods have been 

 abandoned as inefficient and uneeonomieal in comparison, I 

 should feel prepared to advocate or defend a very large and 

 liberal devotion indeed of the public means to setting on foot 

 undertakings, and maintaining establishments, in which the in- 

 vestigation of physical laws and data should be the avowed and 

 primary object, and practical application the secondary, inci- 

 dental, and collateral one. 



"This, however, has hitherto been the fortunate lot of Astro- 

 nomy only. And the result has been, nut only the establishment 

 of a complete theory — 7iot only the perfection of nautical tables 

 and observation — but an universal impulse given to every other 

 branch of exact inquiry — a higher standard erected everywhere, 

 a precision in every determination rendered practicable, which 

 would have never before been dreamed of as attainable vrithout 

 the requirements of Astronomy. Is it hoping too much that the 

 day may not be far distant when Physical Science in all its 

 exacter branches shall participate in these advantages, and when 

 the establishment of ' Physical Observatories ' in our own and 

 distant lands shall give that impulse to many other sciences (as 

 for example Magnetism, Meteorology, &c.) of which they stand 

 so much in need ? " .... "J. F. W. II." 



Trade Winds 



Maury, in his "Physical Geography of the Sea," maintains 

 that the surface trade wind of the northern hemisphere becomes 

 the upper counter current of the south, and z'lce versA. That the 

 trade wind.', in fact, cross each other so — 



instead of meeting and turning tack over themselves so — 



Subsequent writers on physical geography have repeated this 

 statement without apparently reflecting on its extreme impro- 

 bability. 



Maury's arguments for this strange theory are partly connected 

 with the hygrometric state of certain of these currents, partly 

 with ten-estrial magnetism, and partly with the nature of the air- 

 dust. It would take up too much of your space to discuss these 

 points fully. The arguments founded on terrestrial magnetism 

 are, however, purely hypothetical and very fanciful. Those on 

 the hygrometric state of the currents are not very convincing. 

 It is, however, to the latter of Maury's arguments I wish to 

 draw your readers' attention. Maury seems to believe in this 

 almost incredible direction of the air currents because Ehren- 

 berg identified certain South American infusorial fonns in 



the red dust which often falls at sea near the West Coast of 

 Africa and in South Europe. Did Ehrenberg simply identify 

 certain South American forms in the dust, or did he identify the 

 dust as South American on account of the presence of these 

 forms? If the former, the argument goes for little; South 

 American forms may be found in Africa also. If the latter, then 

 a new difficulty arises. Every microscopist knows the curious 

 diversity of infusorial forms in all climates at all similar. It 

 would be the height of presumption even to question the con- 

 clusions of Ehrenberg in microscopy ; and yet to be able to iden- 

 tify infusorial forms in such away asto say that dust containing 

 them comes from such and such a locality is certainly very 

 wonderful. 



Maury, from'some of his remarks, does not seem to be fully 

 alive to the ulter inconsistency of his theory with what we know 

 of the laws of fluid motion. That two broad flat rapid currents 

 should encounter or flow into the same rising current and then 

 cross through each other in alternate strips, or curdles, as Maury 

 calls them, is scarcely within the bounds of physical possibility. 

 On the other hand, Maury's opinions are certainly entitled to 

 consideration, and this is one which he found with so much 

 deliberation, and entertained so firmly, that I should gladly learn 

 what competent physicists of the'present day think of it. 



Graeff Keinet College, Nov. 13 F. Guthrie 



The'Arctic Expedition 



The absence of sunlight during the Arctic winter is said to 

 have an injurious effect on the health of both men and dogs ; 

 yet it does not appear that the best substitute for solar light has 

 ever been employed for illuminating purposes during the dark 

 season. It occurs to me that the occasional use of the electric- 

 light would be likely to mitigate the evils due to the absence of 

 solar radiation, and the constant use of oil lamps. If Gramme's 

 electro-magnetic apparatus could be conveniently used on board 

 ship, it would appear to offer the additional advantage of giving 

 employment to tlie men at a time when it is difficult to find 

 occupation for them. 



Dublin, Feb. 23 R. J. Moss 



Herapath's Balance 

 Can any of your readers inform me whether Herapalh com- 

 pleted his balance, in which he suspended the beam from a 

 magnet ; also whether the idea was taken up by balance makers? 

 He gives an account of this form of balance in a paper dated 

 1821. E. W. P. 



OUR ASTRONOMICAL COLUMN 



The Binary Star \x- Bootis.— Dr. W. Doberck, of 

 Col. Cooper's Observatory, Markree Castle, Sligo, has 

 communicated to the Royal Irish Academy, and also 

 published in Ast. Nach. No. 2026, an orbit of this binary 

 founded upon a very complete discussion of the measures 

 from 17S2 when the duplicity was detected by Sir W. 

 Herschel, to 1873. The resulting period of revolution is 

 290 years, and the true peri-astron passage is found to 

 have occurred about 1863-5. Dr. Doberck does not 

 append an ephemeris of angles and distances according 

 to his orbit, but we supply them for the next eighteen 

 months for comparison with any measures that may be 

 made in the interval : — 



i875'25 Angle i44°79 Distance o"-632 

 7575 „ 142 '83 „ o -634 



76'25 „ 140 -89 „ o -637 



7675 „ 138 -96 „ o -640 



Falb's new Variable in Orion. — The star to which 

 reference was made in Nature last week, appears to be 

 the preceding component of the double star 2 747, or that 

 which was the smaller star during Struve's measures 

 1825-36. Herr Falb has given some particulars relating 

 to this object in No. 2,026 of the Astro)iomische Nach- 

 richten, but we suspect he has inadvertently reversed the 

 order in which the magnitudes of the Dorpat Catalogue 

 should be assigned. Struve's mean is 



i833'59 Angle 223°'o6 Distance 3S"'85 



