NATURE 



433 



THURSDAY, MARCH 9, 1893. 



THEORY OF THE SUN. 

 Theorie du Soleil. By A. Brester, Jz., Docteur ^s Sciences. 



(Amsterdam : Johannes Miiller, 1892.) 

 r^R. BRESTER'S preliminary account of his new 

 ^"^ theory of the sun has already been noticed in our 

 columns (NATURE, vol. xxxix. p. 492). The present volume 

 is a communication to the Amsterdam Academy of 

 Sciences, and gives a complete statement of the principles 

 and their application to the various solar phenomena. 

 The author is careful to point out that he has not con- 

 tributed a single fact of observation himself, but is content 

 to rely on the work of others. Nevertheless, he is evi- 

 dently a most careful student, and if his theory cannot 

 be accepted, some of its points are well worth the atten- 

 tion of solar physicists. 



Starting with the sun as a mass of incandescent 

 vapours, it does not seem unreasonable to regard, with 

 Dr. Brester, the conditions of such a mass of vapour from 

 a purely chemical point of view. At certain temperatures 

 combinations of some substances will become possible, 

 heat will be developed, and various phenomena may be 

 produced. Dr. Lohse ^ has already suggested that this 

 kind of action might be the cause of the outburst of a new 

 star. 



Dr. Brester appears to unreservedly accept Mr. Lock- 

 yer's view, that many of the substances with which we 

 are familiar in our laboratories are dissociated into their 

 finer constituents at solar temperatures. 



In accordance with the generally accepted notion, he 

 also assumes the sun to be gaseous, and regards the 

 photosphere as a shell of partially condensed matter. He 

 rejects, however, the idea that the sun is in an almost 

 constant state of agitation. Indeed, the unique point of 

 his theory is that the sun is always in a state of perfect 

 tranquillity, and that the so-called "eruptions" do not 

 really indicate the actual displacement of matter, but 

 simply the translation of the luminous condition. He 

 boldly declares (p. 4) that " the solar eruptions do not 

 exist," and looks to the known facts of chemistry to ex- 

 plain the multitudinous phenomena with which students 

 of solar physics have to deal. 



What Dr. Brester calls " New Astrochemical Princi- 

 ples " are stated as follows : — 



Principle I. — All incandescent celestial bodies are 

 tranquil in themselves, and their quiet interiors are such 

 that the molecules of different densities, arranged by 

 gravitation in concentric spheres, never lose their stratifi- 

 cation. 



Principle //. — The continued cooling of stars generally 

 produces in their exterior layers an intermittent transfor- 

 mation of chemical energy in the form of heat, and thus 

 produces periodical eruptions of heat. 



Let us see how, with these premises, Dr. Brester 

 treats some of the problems of solar physics. 



The Formation of Spots. — According to the new theory, 

 spots are openings in the photosphere produced by the 

 heat developed in the chemical combination ofdisso- 



1 Berlin Akad. Monatsb., 1877, p. 826. 



NO. I 2 19, VOL. 47] 



ciated molecules, part of the photosphere being evapor- 

 ated when such an " eruption of heat " occurs. On this 

 supposition the spot has the same temperature as the 

 photosphere itself, the condition of things being some- 

 what similar to that of small pools of water in a mass of 

 ice. Dr. Brester shows how this view gives an explana- 

 tion of the proper motions and other phenomena of spots, 

 but we must needs refer those interested to the book 

 itself for full details. 



The Stratification of the Sun's Atmosphere.— AW 

 solar physicists agree that in the solar atmosphere there 

 is a stratification of some sort, but there are different 

 views as to the exact nature of it. The old idea was that 

 each vapour extended from the photosphere upwards, 

 reaching to a height depending upon its density. This 

 view had its birth in the observations showing that all 

 the bright lines of the chromosphere appear to reach the 

 photosphere, but Mr. Lockyer showed,^ that as we have 

 not to deal with a cross section in the observations, the 

 same result would be obtained if the vapours were 

 arranged in true shells. Mr, Lockyer follows up this 

 important fact with the suggestion that the various layers 

 are really concentric shells arranged according to their 

 heat-resisting power, any particular substance finding its 

 level where the temperature is just below that of dissocia- 

 tion for the vapour in question. Dr. Brester, however, 

 goes back to the old view that the layers are arranged in 

 the order of their specific gravities, but modifies it by sup- 

 posing, with Mr. Lockyer, the vapours to lie in shells. 

 Further, accepting the dissociation hypothesis, he re- 

 gards some of these layers as finer constituents of what 

 the chemists call elements, 



Dr, Brester imagines that Mr, Lockyer's view demands 

 that the most dissociated, and therefore the lightest 

 molecules, should be found in the layers nearest to the 

 photosphere, while the least dissociated, and therefore the 

 heavier molecules, should appear in the outer layers. 

 This, however, is not the case, accordmg to our author ; 

 ' the lighter vapours, such as the hypothetical- /i^//«w and 

 j hydrogen being furthest removed from the photosphere ; 

 j while the heavier, such as iron, appear only in the lower 

 levels. The whole subject has been very fully discussed 

 by Mr. Lockyer in his " Chemistry of the Sun," and 

 space does not here permit all the arguments to be re- 

 stated. It may be mentioned, however, that, as Mr. 

 Lockyer points out (p, 172), there is no evidence that the 

 various metals are arranged according to densities ; the 

 case of magnesium and sodium is instanced, the heavier 

 metal always showing the longer lines. 



In a foot-note on p, 17 Dr, Brester states that the 

 various elements need not always appear exactly in the 

 order of their specific weights, " Car la hauteur ou seront 

 encore visibles les molecules d'une mati^re quelconquene 

 dependra pas uniquement de leur poids mais de leur 

 nombre aussi," It is by this bare statement that he 

 attempts to explain the great height to which the H and 

 K fines of calcium have been shown by recent photo- 

 graphs to extend, and presumably also such cases as that 

 of magnesium and sodium, which has already been re- 

 ferred to. It is unnecessary to say more on this point, as 

 Dr. Brester practically renounces this point of his theory 



1 " Chemistry of the Sun," p. 305. 



