-for binding them. 
Fuly 10, 1873] 
NATURE 
199 
VALENTIN’S QUALITATIVE ANALYSIS 
A Course of Qualitative Chemical Anaiysis. By William 
George Valentin, F.C.S., Principal Demonstrator of 
Practical Chemistry in the Royal School of Mines 
and Science Training Schools, South Kensington. 
(London: J. and A. Churchill. 1873.) 
So is a good sign of the present activity of scientific 
study in this country that there should have already 
been a call for a second edition of a work which only 
appeared two years back, in the early part of 1871. 
The author has, in the second edition, separated the 
second part of his orignal work, and this, treating entirely 
of qualitative analysis, forms the volume now before us, 
The elements which occur in the main as bases are 
divided into five groups, and the first portion of the book 
is devoted to a careful study of each element of each 
group beginning with group V., a method the advantages 
of which will be seen by a very short study. The first 
103 pages are devoted to this matter, and the attention of 
the student is then devoted to the study of the reactions 
of the acids. No particular grouping is here attempted, 
the acids being simply taken under the head of the prin- 
cipal element of each, ¢,g. sulphuric acid is followed by 
sulphurous acid, and that by hyposulphurous and hydro- 
sulphuric acids. We remark here, by the way, that the 
polythionic acids are dismissed with the notice that 
they must be reserved for a more extensive course 
of study. A few of the more common organic acids 
are then referred to, and the whole matter treated of is 
shown in the comdensed form as tables. In these we 
notice no important alterations from those of the edition 
of 1871, and of them we can, after considerable expe- 
rience, speak in the highest terms, students soon learning 
to use them with great accuracy and despatch. 
Mr. Valentin has stated in his preface that he 
purposely omits considering the rarer elements in his 
tables. In this we cordially agree with him as regards 
the tables intended for students, but we cannot help 
wishing that Mr. Valentin had put in the appendix some 
analytical information with regard to these bodies in a 
tabular form ; as we feel sure that his great experience in 
the analysis of every possible kind of body would have 
enabled him to give valuable information to many who 
are compelled occasionally to make diligent search for 
elements which are not always met with. Many old 
students of the College of Chemistry will recognise an 
old friend on pp. 50 and 51 in the alternative table for 
group IIIA., it being no other than the old table used 
there up to the time of the introduction of the newer 
methods given at the end of the book. 
We notice with pleasure that the analytical tables 
are published in a separate form, printed on De 
La Rue’s parchment paper; this is certainly very 
good news for chemical students who have to use 
them. Who does not know the gradual process of obli- 
teration and destruction by acids and alkalies which 
gradually, but surely, rendered his most carefully pre- 
pared and written analytical tables useless. It would be 
a great boon to all compelled to use books in the labora- 
tory, if some modification of this material could be used 
In conclusion we can strongly recom- 
mend the book to anyone desiring either to get or to give 
a thorough grounding in analytical chemistry; and the 
only fault we can find with it is that rather too profuse 
use is made of symbolical formule, for they are scarcely 
required in a book on analytical subjects only, and the 
first volume gives quite a sufficient amount of informa- 
tion on their use and nature. We hope that Mr. Valentin 
will some day give us a quantitative analysis. 
R. J. F. 
OUR BOOK SHELF 
Celestial Objects for Common Telescopes. By the Rev. T. 
W. Webb, M.A., F.R.A.S, Third edition, revised and 
enlarged. (London: Longmans, Green, and Co, 1873.) 
PossEssoRS of what Mr. Webb calls “common tele- 
scopes,” will be pleased to have another edition of this 
most useful adjunct to their instruments, with corrections 
and additions up to the present time. Now that silvered 
glass reflectors are so cheap, and apertures little below 
six inches not uncommon in the hands of amateur astro- 
nomers, the author’s definition of a common telescope is 
probably too limited, but these limits are extended as 
we proceed with the book and find mention of objects 
barely visible with nine inches. The advice on the use of 
telescopes, and the mode of observation is sound and good, 
and too much stress cannot be laid on the necessity of a 
good solid stand; a good telescope will be absolutely use- 
less with an unsteady mounting. The description of the 
various phenomena to be viewed in the members of the 
Solar system may lead possessors of small telescopes to ex- 
pect too much, the separation of Saturn’s rings, the mark- 
ingson Jupiter’s satellites, to wit, although mention is made 
of the apertures required to view the features mentioned ; 
but this may also make the book useful for work with 
larger instruments. We must take objection to the great 
contrast of light and shade, as is often the case in other 
works, in the cuts of Venus and Jupiter’s moons, the dark 
markings on Venus being infinitely too black, they in 
reality being only just visible, with first-rate instruments, 
toa practised astronomer. Drawings of this kind only 
represent position and shape, but it must be remembered 
that an amateur expects to see through the telescope ex- 
actly what he sees in a drawing. One-third of the book 
is taken up with a selection of double stars and nebula, 
as in the former editions, with measures of position and 
distance up to later dates. Altogether the book will be 
found most useful to every incipient astronomer, but 
perhaps there may be too strong a tendency to star- gazing 
induced by it, and we should have been more gratified to 
have seen directions to readers having telescopes of cer- 
tain sizes how to make their observations of real use 
and not a mere pastime. For instance, double image 
micrometers can be used on less apertures than 6-in. 
without clockwork ; and some instructions in the use of 
them, and in reducing their observations so as to show 
the motions of binaries, would be of great service in 
teaching amateurs to do useful work; a hint, also, on 
drawing the ever-changing belts of Jupiter, any extra- 
ordinary spots on the sun, the larger nebulz, and last, not 
least, the star clusters. As soon as amateurs have seen 
the planets and a few double stars, they should begin to 
make themselves useful, otherwise they soon get tired of 
the mere star-gazing and the telescope becomes to them a 
thing of the past. G. M.S. 
LETTERS TO THE EDITOR 
[Zhe Editor does not hold himself responsible for opinions expressed 
by his correspondents. No notice is taken of anonymous 
communications. } 
Dr, Sanderson’s Experiments and Archebiosis 
IN last week’s NATURE Dr. Sanderson expresses some sur 
prise that I was gratified by the facts recorded in his previou. 
