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_ FEBRuary 3, 192 Pia 





















































chapter 42, in which an account is given of the use of 
catalysts in organic chemistry, the hardening of oils, 
‘Thiele’s theory and the cracking-of petroleum. An 
extension of the sugar group is given in chapter 39. 
No doubt in a future edition of the book these somewhat 
incongruously grouped subjects will be allotted their 
proper places. 
Minor modifications and additions are the explanation 
of the reactions which occur in the preparation of formic 
acid and of allyl alcohol from glycerol and oxalic acid 
in accordance with Chattaway’s work and Werner’s 
method for the preparation of methylamine from 
maldehyde. Some parts of the chapter on the 
erpenes have been modified, and several new synthetic 
products have found a place. 
(3) Prof. Molinari’s organic chemistry, which was 
translated into English by T. H. Pope, constitutes 
. 2 of his treatise on chemistry. Since its first 
ippearance a second and third edition of the organic 
tion have appeared, the last being so much enlarged 
as to necessitate a division into two parts, each of 
substantial dimensions. The first part has already 
appeared in its English dress, and no doubt the second 
yart, the subject of the present notice, will soon follow. 
Alt! ough this treatise has already been reviewed in 
these columns (NATURE, May 12, 1921, p. 325), it may 
again stated that the organic section is in many 
espects unique. As the title states, it deals with 
general chemistry and chemistry applied to industry. 
The industrial part is not merely a bare text-book out- 
ine of the process, such as the text-book compiler 
scasionally introduces from conscientious motives, 
ut without either knowledge of or interest in the 
ubject. The descriptions are such as might be found 
a specialised treatise dealing with the processes and 
¢ illustrated by excellent diagrams and drawings of 
pparatus, often with cost of plant and appliances. 
foreover, analytical methods and figures are given with 
erous statistics of imports, exports, and prices. 
‘Such a comprehensive combination of the theory and 
ractice of chemistry is in itself illuminating, and one 
‘9 
lay turn over page after page and find a store of 
ormation, of which the non-technical chemist has 
robably never heard. It gives a clear picture, more 
apressive indeed than the splendid “ Dictionary of 
ipplied Chemistry,” of the invasion of industry by 
mce and the widespread extent of that invasion. 
t isa treatise upon which both author and publisher 
id also the translator may be congratulated, and 
feels sure that the friendly appeal of the publisher 
hed to the volume by a slip of paper in which 
_ he “ offre questo volume in omaggio con la preghiera di 
- raccomandarlo agli amici e favorirne la diffusione ” 
_ will find a favourable response. 7. B.C. 
NO. 2779, VOL. 111] 
NATURE 

143 
Our Bookshelf. 
The Old English Herbals. By Eleanour Sinclair Rohde. 
Pp. xii+243. (London: Longmans, Green and Co., 
1922.) 215. net. 
Tue subject of herbals has always attracted students 
of botanical history. The beauty of their figures, the 
quaintness of their language, their appearance as the 
herald of the scientific development of botany, their 
appeal to the folklorist and designer, have all combined 
to create a demand for these books. Dealers have not 
been backward in reflecting the extent of this demand 
in the prices they have put upon them. 
It may be doubted, however, whether the scientific 
student of the history of science will pay quite the 
same importance to these herbals as is attached to 
them by the collector. Undoubtedly the manuscript 
herbals and some of the earlier printed herbals represent 
a stage in the development of science. For the most 
part, however, their preparation has demanded little 
thought—except from the illustrator—and no general 
ideas. Some of the most picturesque of them are 
even behind the scientific development of the time 
in which they appeared. 
Some years ago Mrs. Agnes Arber, in her admirably 
illustrated and arranged work on “ Herbals,” produced 
a scholarly general account of these books. Miss 
Rohde confines herself to those of English origin. 
The choice is, perhaps, unfortunate in one important 
respect since, in fact, few of the herbals which had 
any influence on the course of botany were produced 
in this country. On the other hand, her choice has 
provided an admirable opportunity for giving a picture 
of the attitude towards botanical studies in this 
country in the sixteenth and seventeenth centuries. 
The book, too, is packed with a good selection of the 
very quaintest quotations, by which the sternest critic 
will be at once charmed and disarmed. If they are 
not always relevant they are always entertaining. 
No reviewer will put down the volume without the 
feeling that whatever its faults he has been presented 
with a most readable and entertaining book, and after 
all, what are books for save to be read and to entertain ? 
The would-be writer of the slashing article—if any of 
that iron breed yet survive—will find that Miss Rohde 
has smiled him into good humour long before he has 
turned the second cover. The illustrations, too, are 
excellent, the volume is remarkably cheap, and the 
bibliography useful. 
Essentiais for the Microscopical Determination of Rock- 
Forming Minerals and Rocks. By Dr. A. Johannsen. 
Pp. vi+53. (Chicago: University of Chicago Press. 
London: Cambridge University Press, 1922.) 115. 
net. 
Pror. JoHANNSEN has deserved well of petrologists. 
The present publication by him comprises some half- 
a-dozen tables, explained and illustrated by notes and 
diagrams. The minerals are classed in the first place 
according as they are opaque or transparent, isotropic 
or uniaxial or biaxial, uncoloured or coloured, and 
pleochroic or non-pleochroic, and to each of these 
divisions is allotted a table. In the tables the aniso_ 
