98 



KNOWLEDGE & SCIENTIFIC NEWS. 



[May, 1904. 



effective mass of which was uniformly distributed on the sur- 

 face of a platinum wire. After having been in the dark for 

 many weeks, the platinum selenium surface was covered, at a 

 red illumination, with a sheet of silver bromide jelly to which 

 a sensibiliser absorbing the yellow and green rays was added, 

 an aluminium strip bent at right angles being interposed. 

 After the whole system had been kept in the dark for another 

 48 hours, the same experiment was repeated, using a fresh 

 silver bromide jelly sheet, while a current of about no 

 microamperes traversed the selenium. Now the following 

 results were observed on the developed jelly sheet : — 



In the first case, some bright spots corresponding apparently 

 to the outline of the aluminium angle were noted on a dark 

 background, whereas, in the second case, a dark silhouette 

 of the whole of the angle without any details resulted on a 

 bright background, some brighter narrow transversal bands 

 being visible at the same time. These bands were produced 

 more efficiently in the case of repeated expositions, thus 

 allowing of ascertaining that they are due either to the parallel 

 platinum wires or to the selenium interposed between each 

 two of these, or finally to the points of contact between the 

 platinum and selenium, where the Peltier effect must give rise 

 to an evolution of heat either positive or negative, on the 

 passage of the current. 



On continuing these experiments. Mr. Chabot noted the fact 

 that the back of the plate bearing the platinum selenmm wire 

 was equally capable of affecting the silver bromide jelly, dark 

 silhouettes on bright background being then obtained. As to 

 the question whether these results are an evidence of the 

 existence of some novel radiation, or else an emanation from 

 the surface of conductors, the author hopes to publish in due 

 course some further investigations allowing of more definite 

 conclusions being drawn. 



R-adium a-rvd Heat. 



In the course of an experimental investigation of the in- 

 fluence of radium on the rate of cooling of a body placed in a 

 gaseous medium, Mr. Georgiewsky. in a paper recently read 

 before the Russian Physico-Chemical Society, arrives at the 

 following conclusion : — 



1. The rate of cooling of heated bodies in the various gases 

 is not modified under the influence of radium. 



2. The rate of cooling of non-electric heated bodies placed 

 in one of the gases examined (hydrogen, lighting gas, air and 

 carbonic acidi on being exposed to the action of radium is 

 augmented in the case of the heated bodies being electrified. 

 The rate of cooling in this case will augment not only under 

 the simultaneous influence of the a, S and 7 rays of radium, 

 but as well under the exclusive action of ;3 and 7 rays, 



3. The increase in the rate of cooling of a heated body is 

 greater as the body is negatively charged. 



4. The relations existing between theincreasein the thermic 

 conductivity and the potential of a charged and heated body 

 may be represented by means of curves analogous to those by 

 which Mr. Townsend expresses the connection between a : p 

 and X : p for the same gases {Pliil. Miif;. 6 ser. V. 5, p. 571). 



A. G. 



ORNITHOLOGICAL. 



By W. P. Pycraft. A.L.S.. F.7.S,, M.R.O.U.,&c. 



Breeding Habits of the Common Buzzard 



[Buica vulgaris). 

 Professor J. H. Salter gives an exceedingly interesting 

 account of his observations on the nesting halrits of the 

 Common Buzzard in the '• Zoologist " for March. Of the 

 three young which are almost invariably hatched, he remarks 

 that, in the hill districts, the oldest bird will commonly kill one 

 or both of the younger nestUngs ; apparently for the' purpose 

 of securing their share of the food brought by the parents. In 

 support of this view he points out that this unnatural behaviour 

 is not noticeable when the young are reared in the more fertile 

 valleys where food is plentiful. 



He also describes a curious habit which the parents have 

 of decking the lining of the nest with freshly-plucked leaves 

 and twigs, especially of birch, and rowan, and bracken. 



Birds breeding in Wales furnished the material for this 

 extremely interesting history. 



* ± * 



Greenland Falcon in Donegal. 



It has just come to light that .in inunature bird of this 

 species was trapped in Donegal in December last. This 

 makes the thirty-second record of this species for Ireland, 

 and the tenth for Donegal. 



Nutcracker in Northamptonshire. 



A trap set for " vermin "in February last, at Ty well, captured 

 instead a Nutcracker, whilst one is reported to have been seen 

 in Devonshire during the same month. 



The Emperor Penguin. 



A statement has been going the round of the daily papers 

 to the eftect that one of the results of the newly-returned 

 Discovery Expedition to the Antarctic has been the capture 

 of the Emperor Penguin, a bird which had " not previously 

 been found in these regions." Of course this is a mistake ; but 

 we are glad to learn that the eggs of this bird have been taken, 

 for they have not hitherto been, and will therefore form 

 a welcome addition to the collections of the National Museum 

 at South Kensington. 



All communications intended for this column should be 

 addressed to : — 



\V. P. Pycraft, 



Natural History Museum, 



South Kensington. 



'^i "^i '^^ ^^i ""^i 



REVIEWS OF BOOKS. 



First Causes. 



The Old Riddle and the Newest Answer. By John Gerard 

 S.J., F.L.S. (Longmans.) The old riddle which the Rev 

 John Gerard tries, not to answer, but to state, is that which 

 asks whether it is possible to explain the universe without 

 admitting the existence of a Creator. The answer he gives is 

 that no theory which has yet been formed can relieve us from 

 the necessity of imagining a First Cause ; there must have 

 been a God. a Divine Intelligence greater than any intelligence 

 which man can attain. Mr. Gerard's conclusion is well stated 

 in a quotation from the late Professor Baden-Powell — "That 

 which requires thought and reason to understand must be it- 

 self thought and reason. That which mind alone can investi- 

 gate or express must be itself mind. And if the highest concep- 

 tion attained be but partial, then the mind and reason studied is 

 greater than the mind and reason of the student. If the more 

 it be studied the more vast and complex is the necessary con- 

 nection in reason disclosed, then the more e\"ident is the va.st 

 extent and compass of the intelligence thus partially mani- 

 fested . . . ." But though we have no quarrel with the 

 conclusion that Mr. Gerard reaches, and though we may admit 

 that it has been expressed in varying forms by the greatest of 

 scientific men — by Kelvin, by Lamarck, by Sylvester, even by 

 Huxle}- — there is a distinct objection to the means he has taken 

 to reach it. He opposes the theory of Evolution by the doc- 

 trine of Design. A very large part of his volume is occupied 

 by an attack on Darwinism, which we cannot even admit to be 

 a fair attack. Darwin's theory is not infallible: its too zealous 

 advocates ha\e sometimes stretched it farther that it can legiti- 

 mately be held to go. In any case it is but a working model, 

 and, like the atomic theory, or the theor}^ of the ether, or the 

 chemical theory of ionic dissociation, or the new theories 

 based on radio-activity, it is to be regarded not as a complete 

 explanation, but as a hypothesis which enables us to account 

 for many of the facts. Even if it were completely true, it 

 would not prejudice the belief in a Creator; if it were proved 

 entirely mistaken it would not strengthen that belief. Why 



