162 
NATURE 
[ Fune 30, 1870 
eclipse, is to ascertain, if possible, what is the real nature 
of the mysterious light which forms the corona, and which 
often streams from the solar photosphere in extended and 
fantastic forms. We venture to suggest that, for the pro- 
motion of that calmness of spirit which is essential to the 
successful investigation of scientific truth, the refutation 
of scientific error should in all cases be free from even 
the appearance of strife and personality. But, pass- 
ing from the criticisms on Mr, Lockyer’s theory of 
the solar corona, the fate of Mr. Lassell, the present 
accomplished and experiencea president of the Astro- 
nomical Society, is not more fortunate. Mr. Lassell, 
after years of careful observation with a magnifi- 
cent instrument, unique of its kind, comes to the conclu- 
sion that not more than /owr satellites of Uranus have 
ever been certainly observed. Mr. Proctor, however, thus 
writes : “I have very little doubt that Uranus has at least 
eight satellites.” And again, although our author admits 
that Sir William Thomson seems to have abandoned his 
theory of the probable supply of the sun’s heat and light 
by a battery of meteors, nevertheless he thus writes : “7 
am quite certain* ... . that at least animportant pro- 
portion of the sun’s heat is supplied from the meteoric 
streams which circulate in countless millions around him” 
p. 205). We may fairly ask whence has Mr. Proctor this 
certain knowledge of countless millions of meteoric streams 
impinging on the sun? And how can he, with reference 
to the satellites of Uranus, venture to set his ofznzon in 
antagonism with the results of the protracted observations 
of so accomplished and experienced an astronomer as 
Mr. Lassell ? 
We may call Mr. Proctor’s attention to the Taare 
inadvertency of his description of the hydrozen spectrum 
as white, which it is not in any sense ; and to his 
inexact description of Mr. Carrington’s remarkable ob- 
servation of what may have been a so’ar outburst. Mr. 
Carrington did not use, and he cculd not have used, as 
Mr. Proctor assumes, a dark glass in projecting the 
solar image ona screen, and consequently the alleged 
breaking of this dark glass by the presumed solar out- 
burst, could have occurred in our author's imagination 
alone. These mis-statements, however, are easily cor- 
rigible in a second edition, presuming they are not typical 
of much else in the volume itself. 
We think so highly of Mr. Proctor’s astronomical 
knowledge and general ability, that we have ventured to 
point out what strike us as blemishes in a work which 
contains so much that is suggestive and valuable. Among 
the portions that are most suggestive are Mr. Proctor’s 
remarks on the distribution and motions of the stars 
in streams ; we are far from satisfied that our author 
has as yet made good his case ; but whether his theory 
be correct or not, the suggestions are valuable, and 
afford ample scope for the astronomy of the future. Over- 
looking, however, and forgetting the blemishes, we feel no 
hesitation in recommending this volume to the perusal of 
all who are interested in the progress of one of the noblest 
and most fascinating of the sciences. Some of the plates 
which illustrate the volume are a decided advance upon 
all their predecessors of a like kind, and augur well as 
promises of yet further improvements. 
C, PRITCHARD 
* The italics are ours, 
OUR BOOK SHELF 
Balfour’ Class-book of Botany; being an Introduction to 
the Study of the Vegetable Kingdom. With upwards of 
1,500 illustrations. Third edition. (Edinburgh: A. and 
C. Black, 1870.) 
PROFESSOR BALFouR’Ss “ Class Book of Botany” is too well 
and favourably known to botanists, whether teachers or 
learners, to require any introduction to our readers. It is, 
as far as we know, the only work which a lecturer can take 
in his hand as a Safe text-book for the whole of sucha 
course as is required to prepare students for our university 
or medical examinations. Every branch of botany, 
structural and morphological, physiological, systematic, 
geographical, and paleontological, is treated in so exhaust- 
ive a manner as to leave little to be desired. The illus- 
trations also form, when enlarged, the very best set of 
diagrams that a lecturer can have. After this, it may 
seem hypercritical to find any fault with the new edition. 
We cannot, however, but regret that the opportunity was 
not taken of rendering the book still more complete by 
bringing it down to our present state of knowledge. As 
stated on the title-page, the additions and corrections are 
entirely confined to the department of organography, and, 
as far as they go, are valuable. In particular, the treat- 
ment of the subjects of carpology, inflorescence, and 
phyllotaxis, is rendered much more complete. In other 
departments we have no such additions, and we miss any 
reference to the recent labours of Hildebrand, Parlatore, 
and others, following those of Darwin in the department 
of fertilisation ; of King, Strasburger, and many others in 
the structure of the reproductive organs of Cryptogams, or 
to the remarkable observations of Prillieux, Rose, and 
Brongniart on the movements of chlorophyll. In the de- 
partment of vegetable paleontology in particular, Unger, 
Schimper, Heer, Ettingshausen, Dawson, and Carruthers 
have rendered the science of 1854 scarcely recognisable 
in 1870; and yet we find not a word added, even to the 
first edition. The fault appears to be that the book was 
“stereotyped.” Scientific works ought never to be 
stereotyped. The author has evidently been exceedingly 
cramped in the insertion of new matter, and the correction 
of errors has been rendered impossible. Thus we find 
repeated the old account of the mode of fertilisation in 
Parnassia, which has been shown by both English and 
Continental botanists to be erroneous, and illustrated by a 
drawing which is quite incorrect. The work is ene, how- 
ever, which is indispensable to the class-room, and should 
be in the hands of every teacher. A. W. B. 
Proceedings of the London Mathematical Society. Vols. 
I. and II. 
THIS Society met for the first time in January, 1865. At 
that time the only society in London which received 
mathematical papers was the Royal Society, while the 
Philosophical Society of Cambridge naturally took its 
tone from the university examinations, and paid more 
attention to the proposal and solution of problems than 
to the working out of new principles. The present society 
was formed mainly in order that investigations carried on 
independently over a wide range of subjects might be 
compared, and that from the comparison there might 
grow up some new calculus which should bear to the 
analysis of the present day the same kind of relation that 
integration bears to Wallis’s elaborate investigations of 
the properties of the centre of gravity. There were other 
collateral objects of scarcely inferior importance, such as 
the improvement and extension of the language of mathe- 
matics, the simplification of demonstrations of known 
truths, and the study of the history of mathematics. 
There is scarcely a branch of pure mathematics in which 
the society has not advanced the boundaries between the 
known and the unknown, but the attention of the leading 
members has been chiefly devoted to the higher curves. 
