June 24, 1909] 



NATURE 



503 



M. Coggia observed that on the approach of the 

 shadow's edge, at I2h. 45m. (Marseilles M.T.), Plato took 

 on a red tint, which became redder until, at I2h. join., it 

 appeared like glowing charcoal. 



Mr. J. H. Elgie writes that, according to his observa- 

 tions, at Leeds, the eclipse was a " light " one ; although 

 at its first encroachment the shadow was dead black, when 

 the disc was fully eclipsed many features could be per- 

 ceived by the naked eye. The shadow was first seen, 

 without a telescope, at about 11.45 p.m. Mr. Elgie also 

 directs attention to a curious glow in the northern heavens 

 throughout the night, almost suggestive of an auroral 

 display. 



The Photoheliometer. — In No. 4, vol. xxix., of the 

 Astrophysical Journal (May, p. 313), Prof. Poor describes, 

 and gives the results of, some experiments carried out at 

 the Yerkes Observatory in order to determine the feasi- 

 bility of employing the heliometer method in the endeavour 

 to detect differences in the solar diameters, polar and 

 <quatorial, at different epochs. 



Photographs were obtained with two lenses of 2 inches 

 aperture and 25 feet focal length, mounted side by side in 

 (hi' same cell, so as to give overlapping images of the sun. 



with the film side of the plate turned away from the 

 object, so that when compared, 'film to film, with normal 

 negatives of a different epoch, changes occurring during 

 the interval might be readily detected. 



So far these have only been used for light changes, and 

 not for changes of position produced by proper motion and 

 parallax. Tests recently carried out by Dr. Schlesinger 

 at the Allegheny Observatory show, however, that such 

 plates may safely be used for determinations of changes of 

 position, for observing through the glass has, in the plates 

 tested, produced no serious error, the mean value of the 

 possible error being of the order of oooi mm. On such 

 plates, taken at an interval of ten years, a proper motion 

 of 0025" per annum could be readily detected (Publications 

 of the Allegheny Observatory, vol. i., No. 14). 



THE NEW INSTITUTE OF PHYSIOLOGY AT 



UNIVERSITY COLLEGE, LONDON. 

 T>Y the completion of the Physiological Institute at 

 ^-^ University College, London, which has been erected 

 within the past twelve months upon the site of the play- 

 ground of University College School, the University of 



of Physiology, north elc 



Then two methods of measurement were tried, one in 

 which the diameter passing through the centres of the two 

 images was determined directly, the other in which the 

 solar radius was determined from measurements of the 

 chord common to the two overlapping images. Prof. Poor 

 discusses both methods, and concludes that the second will 

 give the better results. Finally, he concludes that for his 

 researches the photoheliometer is better than the direct 

 photographic method, and gives some practical working 

 hints, e.g. wet plates should be used on account of the 

 sharper, clearer images they give. A series of six trial 

 plates, taken during October and November, 1907, gave a 

 mean excess of equatorial over polar radius of 0-95". 



The Errors of Position of Images photographed 

 THROUGH Glass. — For some time past photographs of star 

 areas have been taken at Harvard College Observatory 



NO. 2069, VOL. 80] 



London possesses what is probably the finest laboratory 

 of its kind in the country, and one which is perfectly 

 equipped both for teaching all branches of physiology and 

 for the pursuit of original research work. The erection 

 of this institute marks an epoch, not only in the history 

 of the re-constituted University of London, but in the 

 development and advancement of the British school of 

 physiology, a school which was practically non-existent 

 a few decades ago, when nearly all research in this subject 

 was carried out in the laboratories of France and 

 Germany. 



It is a matter for congratulation to those who have 

 been instrumental in founding this institute that the sub- 

 ject of physiology is to be both taught and advanced 

 bv original work, for in the creation of this science 

 University College may fairly claim to have played a 



