NOTES. 



ASTRONOMY. 



By A. C. D. Crommelin, B.A., D.Sc, F.R.A.S. 



PROFESSOR J. C. KAPTEYN'S REPORTS OX THE 

 PROGRESS OF WORK ON HIS SELECTED AREAS.— 

 It will be remembered that a few years ago Professor 

 Kapteyn made the suggestion that as the problem of finding 

 the position, motion, spectrum and magnitude of every visible 

 star was too vast for our resources, it would be well to select 

 a series of small areas uniformly distributed over the sky, and 

 that the stars in these areas should be studied with the 

 greatest possible care. He anticipated that in this way most 

 valuable data about the structure of ihc stellar universe might 

 be acquired in a comparatively short time. He was fortunate 

 in obtaining such a large measure of support for his plan that 

 it is already well under weigh, and the reports now to hand 

 take stock of the results acquired and make suggestions for the 

 future. 'I he work of organisation was felt to be beyond the 

 power of one man, and a committee has been formed, 

 consisting of Professor Kapteyn, Sir David Gill, Professors 



E. C. Pickering, G. E. Hale, F. Kiistner, K. Schwarzschild, 



F. W. Dyson (.\strononier- Royal), and W. S. Adams. 

 The following are the positions of the selected areas. 

 The North Pole :— 



Decl. 75° N R.A. O" 0"' and every fourth hour. 



Decl. 60 N. ... ... R..-\. 1 and every alternate hour. 



Decl. 45 N. ... ... R.A. 40 and every hour. 



Decl. 30 N R.A. 25 „ 



Decl. 15 N R.A. 10 



Decl. R.A. 50 



Decl. 15 S R.A. 15 ., 



And a similar continuation for the Southern sky. 



The problem of finding accurate magnitudes is now under- 

 taken far more carefully than it used to be, as very important 

 (juestions of the structure of the universe and the possible 

 absorption of light in space depend upon it. 



The method mainly used is photographic, each region being 

 photographed on the same plate as the standard polar area, 

 the magnitudes in it having been determined at Harvard with 

 the aid of some plates taken with the sixty-inch reflector at 

 Mount Wilson, showing starsdown to the twenty-first magnitude. 

 A series of Durchmusterung plates of the selected regions is 

 being taken by Professor E. C. Pickering, using originally the 

 twenty-four inch Bruce telescope, focal length eleven feet, 

 and subsequently the sixteen-inch Metcalf telescope, focal 

 length seven and a half feet. These plates give tolerably 

 good positions and accurate magnitudes and numbers of stars. 

 They go down to the sixteenth magnitude, and contain about 

 thirteen thousand stars per scjuare degree in the Galaxy, 

 which number falls to six hundred per square degree 60° from 

 the Galaxy. 



The next item in the work is a series of parallax plates of 

 the selected regions. The Cape Observatory is active in this 

 field in the Southern Hemisphere, and has taken one hundred 

 and seventy-six finished plates. 



Father Chevalier, at ZoSe (China) is undertaking a small 

 region, and the Allegheny and Yerkes Observatories are also 

 cooperating. At least two exposures arc made on each plate 

 six months apart, and either a third exposure six months later 

 or a second pair of exposures on another plate I three exposures 

 at half-yearly intervals being required to eliminate proper 

 motion). These are all taken near the meridian, so that the 

 effect of atmospheric dispersion, arising from slightly different 

 colours of stars, is practically constant. This involves taking 

 the region at about six o'clock a.m. at the first exposure, and 

 six p.m. at the second. 



PROPER MOTIONS. — A similar series of plates is being 

 taken to obtain the proper motions of the fainter stars, but 

 the interval must be at least ten years for useful results. It 

 is proposed to keep the plates undeveloped, and re-expose 

 after the interval ; this, however, is not an essential, and a 



beginning can be made by comparing recent plates with those 

 taken for the Carte du ciel ten or fifteen years ago. Besides 

 the observatories mentioned above the Radcliffe Observatory, 

 Oxford, is taking proper motion plates with the twenty-four 

 inch equatorial, and photographs are being taken with the 

 sixty inch reflector at Mt. Wilson of the centres of the selected 

 areas. The region of good definition on these plates is only 

 25 across, but they will enable the magnitudes and countings, 

 and in time the proper motions, to be extended to the 

 eighteenth in.ii'iiitndc. 



BOTANY. 



By Professor F. Cavers, D.Sc, F.L.S. 



VEGETABLE PROTEINS.— Much interesting work has 

 been done during the last few years on the proteins occurring 

 in plants. These bodies are the most complex organic 

 substances known, and they are of great importance from the 

 fact that the protoplasm of plants and animals — " the physical 

 basis of life " — consists essentially of proteins. 



Zaleski (Beih. Bot. Ccntralb'l., Band XXVU. Abt. I) has 

 studied the transformation of nitrogenous materials in ripening 

 seeds, in their relation to the synthesis of proteins. He finds 

 that various organic nitrogen-containing substances, simpler 

 than proteins, are transformed to proteins during ripening. 

 His method is to remove green peas from the pod and make 

 determinations of the nitrogen in proteins, in amino-acids, and 

 in organic bases ; sets of young seeds are taken and treated in 

 this way from time to time, part of each set being analysed at 

 once, the rest after a week, and the analyses compared. In 

 all cases considerable amounts of amino-acids and organic 

 bases were transformed into proteins during storage of the 

 seeds. In peas the s^mthesis was less than half as rapid in 

 the absence of carbon dioxide as in its presence ; drying of the 

 seeds hastened the synthesis considerably. 



According to Zaleski, the amino-acids resulting from the 

 hydrolysis of a plant protein are the ones involved in its 

 synthesis, the two processes being phases of a reversible 

 reaction. This view is taken by various recent investigators, 

 and is opposed to the older views that asparagin is the 

 immediate material from which plant proteins are built up, or 

 that proteins may be synthesised by the introduction of 

 ammonia into simple organic compounds. Possibly the same 

 enzymes (ferments) cause both the building-up and the breaking- 

 down of proteins. 



DEVELOPMENT OF LAMINARIACEAE. — As noted 

 in these columns some time ago (" Knowledge," September 

 1910), it has been found that the so-called "zoospores" of 

 Laininaria, the "' sea tangle," are in reality sexual cells 

 (zoogametes) which fuse in pairs, the resulting fusion-cell 

 (zygote) producing a chain or mass of cells from which 

 the Laininaria plant arises. 



Killian iZcitschrift fiir Botaiiik, III) has made a thorough 

 investigation of the early growth of Laminaria from the 

 confervoid protonema stage, and has also brought together 

 the scattered though extensive literature of the Laminariaceae, 

 adding many interesting observations of his own regarding 

 the anatomy, regeneration, and general biology of this group. 

 He finds that from the primary few-celled protonema there 

 arise secondary protonemata which for a time undergo repeated 

 cell-divisions in all directions and remain at first uniform in 

 structure, but later there is localised growth and specialisation 

 of the tissues. All the tissues are genetically connected 

 together. The inner tissues are distinguished by their feeble 

 power of growth and division, hence they play a passive part 

 and their original arrangement undergoes disturbance ; the 

 primary connections between these inner tissues are lost, and 

 new tissue-elements are interpolated from the outer zone. 

 The Laminariaceae agree closely in histological structure 

 with the Fucaceae. All parts of a Laminaria plant respond 

 rapidly to wound stimuli, regeneration being quickly and 

 completely effected when these parts are injured by cuts 



