620 
NATURE 
[ Oct. 28, 1886 
we want to know whether it is the large or the small form 
which he met with. Again, on p. 73, when he talks of 
the “sheet of water or marshy ground which might attract 
the waders and sea-birds so commonly found near Ox- 
ford,” is it not the east wind which drives the latter along 
the course of the Thames, rather than any peculiar at- 
traction of the country near Oxford? The fact of the 
Cuckoo carrying her egg in her bill for deposit in the 
nest of her victims is now universally admitted ; but 
what concerns ornithologists is the greater or less re- 
semblance of the egg deposited by the female Cuckoo to 
the eggs of the foster-parents which she selects to bring 
up her young. The Spotted Flycatcher has undoubtedly 
a song (p. 83), but it is a poor affair, and is heard only, 
according to our experience, at daybreak. It is true that 
the Green Sandpiper (p. 86) has really only the legs 
greenish, but the reason of the perpetuity of the name to 
which our author objects, is because Linnzeus called the 
species ochrofus, and the name adopted by the older 
English writers was the Gree Sandpiper, which has been 
handed down to the present generation, as is also the case 
with the Grey Wagtail. The author knows his “ Dresser” 
and his “ Harting,” but he can learn something of the 
affinity of Robins and Redstarts (pp. 88, 101) from Mr. 
Seebohm in the British Museum “ Catalogue ” (vol. v.), or 
in his “ History of British Birds.” The little essay on the 
“Birds of Virgil” is most interesting, especially with 
regard to the A/cyon, which, we agree with the author 
and his authorities, was probably zo¢ our Kingfisher, 
though the presence of the latter on the sea-shore in 
some numbers is a fact at the season of the autumn 
migration, We offer these few remarks to the author as 
points of further study on which we should be glad to 
have the observations of a true naturalist, such as he 
evidently is. 
The Rev. Gregory Smart has recently published a little 
book on the ‘ Birds on the British List,” which is a 
critigue on the list issued by the British Ornithologists’ 
Union, which he collates with the works of Mr. Dresser, 
Mr. Seebohm, and the fourth edition of ‘ Yarrell.” The 
book is disfigured by a slovenly style of writing, for 
which the printers’ errors can scarcely account, and this 
is the greater pity, as the author’s intentions are good, 
and he scores distinctly on several occasions when dis- 
secting the evidence on which some birds are admitted to 
the British List while others are rejected ; but the Eng- 
lish in which he endeavours to record his conclusions 1s, 
to say the least of it, a little mixed. The author con- 
fesses to “having had but little experience,” and it would 
therefore have been better to have restricted himself to 
the main object of his book, viz. the criticism of the 
evidence on which some species are retained or re- 
jected in the works above alluded to. When he gets 
outside the boundary of his crztégue, he talks in some 
instances simple nonsense, as in his remarks on the 
Gold-vented Bulbul (p. 18). Mr. Dresserand Mr. Bidwell, 
in aiding and abetting Mr. Smart in his hap-hazard identifi- 
cation of his Bulbul’s egg, could scarcely have expected the 
punishment of having their rash opinion published to the 
world. On p. 41 some more nonsense appears about 
Anthus ludoricianus and A. campestris being conspecific ! 
The author would seem to be unaware that ‘‘ Ungaru” 
is generally spoken of as “ Hungary ” by English writers, 
and that ““Los Angelos Cala” is a locality which will 
puzzle many an “inexperienced” collector for whose 
benefit Mr. Smart professes to write. We would advise 
the author, before publishing another book, to get some 
friend to look over his manuscript for him, as a good 
deal of the difficulty of unravelling the meaning of his 
sentences would have been avoided by a simple attention 
to stops and commas, which is not too much to 
expect from a “late Scholar of Trinity College, 
Cambridge.” 
R. BOWDLER SHARPE 
SOLAR PHYSICS} 
M OST of our readers are aware that the sun, as con- 
structed by Zéllner, was a white-hot, liquid body, 
that its spots were scoriaceous products of local cooling, 
and that its atmospheric circulation was closely modelled 
upon the terrestrial, with trades and anti-trades, an 
equatorial belt of calms, land- and sea-breezes, the last 
due to the contrast of temperature between the slag- 
islands constituting spot-nuclei, and the incandescent 
ocean in which they floated. On these lines M. Schulz 
has reared a solar edifice out of materials to a large 
extent new. Sixteen additional years of results in one of 
the most rapidly progressive branches of modern physi- 
cal astronomy, give him an advantage over his prede- 
cessor, utilised to the utmost in modifying, extending, and 
generalising views of which he is the intrepid, though 
not blind, partisan. The upshot, we venture to assert, is 
to prove them wholly untenable. If M. Schulz’s inge- 
nious advocacy fail to recommend them, their inherent 
weakness must be great. Our readers shall judge for 
themselves of its success. 
In the work before us it is undertaken to account for 
the whole array of solar phenomena, from the conserva- 
tion, through long geological ages, of the solar activity, 
and its cyclical fluctuations, to the production of a pore 
ora facula. With this alluring prospect in view we are 
invited to regard the sun as a liquid globe composed of 
unknown substances, glowing at a temperature some- 
where between 10,000° and 20,000°C. Although the 
heat rises towards the centre by a very low gradient, the 
inequality suffices to insure the distribution of the loss by 
radiation throughout the bulk of the globe, vertical con- 
vection-currents carrying down the cooler and heavier 
outer layers, and replacing them with hotter and more 
buoyant materials from the interior. Thus the danger is 
averted of the light-and-heat-giving career of our lumin- 
ary being brought to a premature close by the untimely 
formation of a crust. The relative permanence of that 
career is further secured by the application to a liquid 
sun of Helmholtz’s gravitational principle of the main- 
tenance of solar heat. 
The extensive atmosphere surrounding this molten mass 
is composed mainly of the unknown gas emitting Kirch- 
hoff’s “1474” line. This, in M. Schulz’s opinion, is the 
primitive and simplest form of matter. Its atoms, many 
times lighter than those of hydrogen, are the fundamental 
units by the various aggregation of which the atoms of all 
other substances whatscever are constructed. It plays, as 
we shall presently see, a very important part in the solar 
economy devised by our author. The solar supply of it 
is on a prodigious scale, since it fills, mixed with small 
percentages of hydrogen, helium, and metallic vapours, 
the vast spherical shell visible during total eclipses in the 
form of a “corona.” 
In the lowest strata of this gaseous envelope the photo- 
sphere hangs suspended at a height of a few thousand 
miles above the real surface of the sun. Its structure 
resembles that of our cirrus-clouds, only that metallic and 
incandescent condensing particles are substituted for 
aqueous frozen ones. The Fraunhofer absorption M. 
Schulz brings about by the customary machinery of the 
“reversing layer,” regardless of the growing objections 
on the part of leading solar physicists to its exclusive em- 
ployment in that capacity. Indeed the details of spectro- 
scopic evidence scarcely receive from him the minute 
attention they deserve. Mr. Lockyer’s researches on 
“lines widened in spots” give an example of the kind 
of work that has henceforth to be done on the solar 
spectrum. Summary explanations of its phenomena no 
longer suffice. Each one of its thousands of dusky rays 
has an individual story to tell, well worth the trouble of 
Von J. F. Hermann Schulz. Separatabdruck 
t “Zur Sonnen-Physik.” Z c 
(Leipzig: W. Drugulin, 
aus der Gaea, Bande xxi. und xxii., 1885-86. 
1886.) 
ed ee ae 
