254 



SCIENCE 



[Vol. LVI, No. 1444 



most of them. On one a face was visible in the 

 midst of a cotton- wool effect; the others had 

 crude markings, ascribed by the medimn to un- 

 formed "ectoplasm" or to "spirit lights." As 

 will be observed, she had acquired some of the 

 latest spiritualistic terminology. At the second 

 sitting, arranged by Mrs. McKenzie, a sealed 

 box of sis plates, forwarded in accordance with 

 instructions, was produced by the medium. 

 The box was opened and the plates transferred 

 to metal dark slides; a service was then held, 

 hymns being sung, and the Lord's Prayer re- 

 cited. The plates were then exposed and an 

 "extra" appeared on one of them — on No. 1 

 plate — which the investigators satisfied them- 

 selves had been substituted for the first plate 

 of the original package. The medium had by 

 this time become suspicious and nervous, and 

 in fact she was not equal to holding her own 

 with professional conjurers. She, however, 

 consented to a third sitting, and for this an un- 

 opened box of unprepared plates was sent. It 

 therefore became necessary that the plates 

 should be secretly marked before being placed 

 in the dark slides. One of the investigators, 

 having placed the open stack of plates before 

 the medium under the ruby light, secretly 

 attached a small pad of pink material, chem- 

 ically prepared, to the ball of his right thumb, 

 and in handing the plates one by one to the 

 medium an invisible mark was impressed on 

 each. The medium gathered up the slides, and 

 going into the studio took them to a small table 

 on which her handbag was standing. The 

 ostensible object was to obtain the hymn-books 

 for the service, but the move being anticipated, 

 the members of the deputation placed them- 

 selves in convenient positions to observe her 

 actions. The hand holding the slides was seen 

 to be placed inside the bag; one slide was 

 dropped into a side pocket and a duplicate 

 slide picked up with the hymn-books. Four 

 plates were developed, and on one which did 

 not show the mark a "spirit extra" appeared. 

 All this may be amusing to the cynic, but the 

 conclusions the committee of the Magic Circle 

 draw are that although spirit photographers, 

 like conjurers, meet changing conditions by the 

 adoption of new methods, there are at present 

 at least two methods in general use by some. 



at least, of the mediums who devote themselves 

 to obtaining photographic "extras." In the one 

 case, when the plates are accessible before the 

 sitting, the spirit form is impressed, in ad- 

 vance, by contact with a selected transparency. 

 In the other, when the packet is not available 

 beforehand, the exchange for a prepared plate 

 is made by a subtle move after the original 

 plates have been loaded into the dark slides. 

 The committee assert that they have never im- 

 posed a test which would not have served to 

 demonstrate the straightforwardness and hon- 

 esty of the medium, and conclude with a prom- 

 ise to extend to any honest medium fair, im- 

 partial and courteous treatment, and to give 

 him a free hand to carry out the experiment in 

 his own wav. — British Medical Journal. 



SCIENTIFIC BOOKS 



The Evolution of Climates. By Marsden Man- 

 son. 1922. Published by the author. 

 Dr. Manson has been long and widely 

 known as a student of geologic climates. 

 When his attention was first directed to the 

 subject the currently accepted theory — which 

 indeed still persists — posltulated the solar con- 

 trol of terrestrial temperatures similar to that 

 which now dominates such temperatures, but 

 it early became apparent that not all of the 

 problems presented could be satisfactorily 

 solved under this assumption. For instance, 

 the non-zonal distribution of climates such as 

 certainly obtained during at least the major 

 part of pre-Pleistocene time, the frequent re- 

 currence of mild temperatures in polar areas, 

 glaciation at or near sea level in and adjacent 

 to the tropics, etc., have not been satisfactorily 

 explained on the basis of exclusive solar con- 

 trol. This leads to the postulate of a dual heat 

 supply — that is a part derived from the earth 

 itself and a part from the sun. The manner 

 in which this postulate works out and the 

 solution it seems to afford to the various prob- 

 lems involved is set forth in the present paper. 

 In 1903 Dr. Manson published a preliminary 

 paper under the same title as the present one, 

 in which he reviewed the various theories that 

 have been proposed to account for the origin 

 and distribution of climatic differences, and 



