NOVKMBER, 1903.] 



KNOWLEDGE 



257 



forward. The natural assumption appears to be that it 

 is connected wi I h the "advertising department," that in 

 some way it makes the flower-head more conspicuous to 

 insects, and thus helps cross-fertilization. There are 

 numerous instances of white flowers being used for 

 this purpose {e.g., in the Daisy), but I cannot think 

 of an instance where the abnormal flowers are darh. 

 — E. Lloyd Praegee.] 



MAN'S PLACE IN THE UNIVERSE. 



TO THE EDITORS OF KNOWLEDGE. 



Sirs, — Will you allow me to express my dissatisfaction 

 with Mr. Maunder's article in your current number upon 

 the above question ? Dr. Wallace's position, as to our 

 place in the universe, is, that whatsoever evidence we have 

 goes to support the conclusion that we are placed in or 

 near the centre of the stellar universe ; and that the 

 universe itself is limited in extent. For the first point. 

 Dr. Wallace has the support of the following evidence 

 adduced by Sir Normau Lockyer: — "The stars in question 

 in the Milky Way, which is a great cii'cle, are all equally 

 remote ; and the only place where such a state of things 

 can be observed must be a point equally distant from all, 

 that is, in the centre of the system under observation. It 

 is worth while to repeat, that because we are in the centre, 

 because the solar system is the centre, that the observed 

 effect arises" {Nature, November 8th, 1900). 



For the limited dimensions of the universe there is the 

 dynamic principle adduced by Lord Kelvin to show that 

 the velocity of the stars in their drift is only compatible 

 with a universe of limited dimensions. Now it is a very 

 unsatisfactory reply to these things to speak of what may 

 be, which, moreover, is a very unscientific position to take. 



Maidstone, October 9th, 1903. W. Woods Smyth. 



[Neither Sir Norman Loekyer's nor Lord Kelvin's argu- 

 ments in the least support Dr. Wallace's position. Mr. 

 Woods Smyth must remember that the whole object of 

 Dr. Wallace is to prove that our solar system is the only 

 one in which intelligent life is possible. He assumed that 

 if he could prove that our sun was in the centre of the 

 universe this would follow. It was a mere assumption, 

 which he has practically withdrawn ; but let that pass. 

 Admitting its validity, it was still necessary for him to 

 prove that our sun was much nearer to the centre of the 

 universe than was the case with any other sun whatsoever. 

 Neither of the two authorities quoted help him here. — 

 E. Walter Maunder.] 



STELLAR SATELLITES. 



TO THE EDITORS OF KNOWLEDGE. 



Sirs, — Mr. Gore, in his article under above title, in 

 Knowledge for September, refers to the companion to 

 Procyon. I think Burnham with the 36-inch failed to see 

 this at all from 1888 to 1891 (see Lick Publicationa, page 

 63). Has it been seen since? If so, by any one except 

 Schaeberle V 



Mr. Gore refers also to the double companion to Rigel. 

 I think Burnham afterwards doubted his observation of 

 I87I. At any rate he found it single in 1889-1892 

 (see Lick, page 43). 



Mr. Gore refers to what he calls " this rule," that most 

 of the known binaries are of nearly equal brightness. I 

 think the use of such words as " rule " and " law " is often 

 objectionable. They imply more than is intended. But 

 in the case referred to is it not — so far as it is a fact — 

 because unequal binaries are much more difficult to 

 discover and to observe ? I don't think there is sufficient 

 evidence that they are less numerous. 



In another instance he says there are some stars which 



do not show orbital motion " which are known to be 

 phvsically connected." In the next sentence he says "they 

 are most probably near enough to be linked together by 

 the laws of gravitation." But does not knowledge 

 transcend probability? If they are known to be physically 

 connected, are they not more than probably linked together 

 by gravitation ? 



" Mr. Gore also seems to use the word brightness in- 

 differently for quantity of light and surface brilliancy. T 

 know this is a very common practice, but it is a very 

 awkward one. 



Mr. Gore's speculations are very interesting, and would 

 be more so if the parallaxes he uses were reliable, but 

 when he calls a parallax of 0"0.54 only "somewhat" 

 doubtful he uses a very mild expression about it. 



Edwin Holmes. 



jaottc ra of iS ooftg. 



"TuE PO.5ITI0N OF Till; I »r.ri Rfii Sandstone in the 

 Geological Succe-sshin.' By A. G. il. Thomson, f.g.s. 

 (Leng & Co ) — Tbis well-printed book has been issued with all 

 seriousness, and with no "controversial intention" (p. "224). 

 The author frankly styles his views " hypotheses," but unfor- 

 tunately appears to be ignorant of the long discussion which 

 has moulded geological opinion as to the position of the Old Red 

 Sandstone. He is unaware that he might have quoted the 

 illustrious name of Jukes in support of his proposal (p. 97) to 

 regard the Carboniferous and Devonian strata as contem- 

 poraneous facies of a single system (see 'Juurt. .Joui-n. Geol. Soc, 

 Vol. xxii., 1866, pp. 367-9). Mr. G. H. Kinahan, boldly carrying 

 out Jukes's suggestions, has, moreover, anticipated Jlr. Thomson 

 as regards the intercalation of Old Red Sandstone conglomerates 

 in the Carboniferous system (p. Oo). It might have been 

 expected that an author so anxious to improve upon our present 

 knowledge would at least consult our current text-books. .Sir 

 A. Geikie, for instance, stated the case clearly ten years ago in 

 his " Text-book of Geology" (."ird edition, p. 778): and the 

 expanded form in which his remarks now appear (4th edition, 

 1903, pp. 981-'2) should prove still more instructive to Mr. 

 Thomson. He will learn from those excellent passages that 

 geologists in general do not regard the Old Red Sandstone as of 

 necessity conterminous with the marine Devonian sj'stem ; but 

 he will also find that the continental evidence for independent 

 Devonian and Carboniferous systems has long proved fatal to 

 the hypothesis of Jukes. Mr. Thomson, however, with a fine 

 disregard for both stratigraphy and palajontology, considers that 

 the Silurian beds containing fish-remains, and the Devonian and 

 Carboniferous systems, represent varying types of deposit which 

 het/ini to be laid down at the same time side by side (pp. 49, 70, 

 etc.). The British Coal-measures are for him a huge drift- 

 deposit, brought in suddenly from some other quarter of the 

 globe. The Atlantic Ocean and the American Continent 

 (p. 36) are held to have existed in the Palicozoic era. The 

 evidence as to the vast extent of post-Carboniferous denudation 

 in our islands (p. 59) is absolutely overlooked. We gather from 

 p. "218 that the variety of fresh-water, brackish- water, and 

 marine deposits recognisable in our coal-bearing strata have 

 never been seriously examiuod by the author. Mr. Thomson 

 writes modestly throughout, but he has entered the field with a 

 disregard for pioneers which will hardly commend him to the 

 scientific reader. 



"Raihum and Otiieu Radio- Active Substances: PoLONiuir, 

 AcriNiu.M, and TiiOKiUM." By William J. Hammer. (Sampson 

 Low.) 5s. net. — Few discoveries have ever been received with 

 greater interest than that of the radio-active properties of 

 radium and its congeners. In the first place, it appeals to the 

 sense of the marvellous which is present in all of us, and this 

 none the less that old and app.arently well-established laws seem 

 to be violated by it. A few milligrams of radium, we are told 

 by Prof. Curie, when introduced beneath the skin of a mouse 

 near the vertebral column, i)i'oduced death by paralysis in three 

 hours. The introduction of radium into the science of chemistry 

 will produce — who knows what ? Already Prof. Armstrong, 

 " speaking as a chemist.'" can saircely express his astonishment 

 at the audacious physicists who are opening up a new world to 



