TRANSACTIONS OF SECTION A. 557 



in due season or it may not. I must return to the work of this section, from 

 which I have apparently wandered rather far afield, further than is customary — 

 perhaps further than is desirable. 



But I hold that occasionally a wide outlook is wholesome, and that without 

 such occasional survey, the rigid attention to detail and minute scrutiny of every 

 little fact, which are so entirely admirable and are so rightly here fostered, are apt 

 to become unhealthily dull and monotonous. Our life-work is concerned with the 

 rigid framework of facts, the skeleton or outline map of the universe ; and, though it 

 is well for us occasionally to remember that the texture and colour and beauty which 

 we habitually ignore are not therefore in the slightest degree non-existent, yet it is 

 safest speedily to return to our base and continue the slow and laborious march with 

 which we are familiar and which experience has justified. It is because I imagine 

 that such sj'stematic advance is now beginning to be possible in a fresh and unex- 

 pected direction that I have attempted to direct your attention to a subject which. 

 if my prognostications are correct, may turn out to be one of special and peculiar 

 interest to humanity. 



The following Reports and Papers were read : — 



1. Jnterim Report of the Committee on Phenomena connected with 

 Recalescence. — See Reports, p. 147. 



2. On the Action of a Planet upon small Bodies passing near the Planet, 

 with Special Reference to the Action of Jnpiter upon such Bodies. By 

 Professor H. A. NEWTON.^See Reports, p. 511. 



3. Oil the Ahsorption of Heat in the Solar Atmosphere. 

 By W. E. Wilson, M.R.I.A., F.R.A.8. 



The author endeavours to determine with accuracy the ratio of the heat 

 received from the limb and the centre of the solar disc, and thus, by taking yearly 

 observations through a sun-spot cycle, to find out if the solar atmosphere varies in 

 depth. 



The apparatus consists of a heliostat which throws a small pencil of sunlight 

 into a dark room. It is received on a 4-inch concave silver-on-glass mirror of 

 about 10 feet focus. A small convex mirror is placed inside the focus of the 

 concave mirror, and thus forms an image of the sun of 80 centimetres in diameter. 

 This image is allowed to fall on a radio-micrometer of Prof. C. E. Boys. The tube 

 of the instrument is stopped down to nearly 1 mm. in diameter, so that only about 

 Boo5oo P*''^'^ *^f *^^ solar image is at any moment giving its heat to the instrument. 



A slice of limelight is allowed to fall on the mirror of the radio-micrometer, 

 and is reflected from it on to a horizontal slit in the side of a box which contains 

 a photographic plate. This plate duiing an observation is allowed to fall with a 

 uniform rate by a piece of clockwork. Any motion of the mirror of the radio- 

 micrometer thus records itself on the plate in a curved line. 



The clock of the heliostat is stopped and the image of the sun is allowed to 

 transit across the mouth of the radio-micrometer, and the curve giving the values 

 of the heat received from the solar disc is recorded on the photographic plate. 



A seconds pendulum swings across the track of the limelight, so that the 

 photographed curve is notched into seconds of time, and a means thus given of 

 localising the position of the instrument on the solar disc. 



4. The Ulfra-Violet Spectrum of the Solar Prominences. By Professor 

 George E. Hale, Director of the Kenwood Physical Observatory, Cliicayo. 



The prominence spectrum has been photographed with a large solar spectro- 

 scope attached to the 12-2 inch equatorial refractor. Several new lines have been 



