ow oh 4 ; rod | Be MY a) BLY >) = 
DrEcCEMBEK 13, 1906| NATURE 147 
and geology at Jena has attempted to do justice to this | preparation of a mineralogical map of the Ilmenau 
side of Goethe’s activity. Realising the danger of | district, subsequently extended to neighbouring 
unconsciously misrepresenting’ Goethe’s position by | regions. It bore further fruit in several practical sug- 
attempting to interpret his worl in the light of our pres 
sent knowledge, Prof. Linck has wisely allowed 
Goethe to explain himself in extracts from his pub- 
lished writings and correspondence. Goethe appears 
to have been attracted to the study of mineralogy partly 
by the reopening of the Ilmenau mines, and partly 
through the influence of the Freiberg school. Further, 
his official position brought him into contact with min- 
ing and geological problems, and his business instincts 
led him to take an interest in any discovery likely to 
be of practical use. 
Goethe, in fact, was by nature a realist, and even his 
muse was happiest when inspired by a striking event 
or by a beautiful scene. His realistic tendencies led 
him to become an ardent collector of minerals, rocks, 
and fossils, which he regarded from a natural history 
point of view. But he lived in a time when the classi- 
fication of minerals by their more obvious external 
characters and by their mode of occurrence was passing 
away. On the one hand, analytical chemistry was 
revealing their composition; on the other, crystallo- 
graphy was reducing to order the apparent complexity 
of the erystal forms. Goethe, however, held by the 
oid system. He realised, it is true, the importance of 
chemistry— I cannot get a step further in mineralogy 
without chemistry ’’— but it was a study for which he 
appears to have had but little aptitude. His appre- 
ciation of crystallography was smaller still; witness his 
statement, ‘‘ Crystallography is not productive—and 
leads to no results, especially now that so many iso- 
morphous bodies have been discovered of different com- 
positions.’’ Goethe appears, indeed, to have regarded 
the progress of these sciences with some misgiving, 
for he says :—‘‘ Mineralogy is in danger of being 
devoured by crystallography, where form is all-im- 
portant. It isin danger of being devoured by chemis- 
try, which looks only for general laws and is indif- 
ferent to form. It may also be in danger of being 
devoured by geology, for the latter is only concerned 
with modes of occurrence.’’ As an adherent, then, 
of a system which had attained practically the fullest 
development of which it was capable, the field open 
to him was not extensive, but within its limits 
he did good work. His description of the Carlsbad 
felspar twins, for example, was excellent, and we 
owe many interesting observations to his studies 
on crystal-genesis and on the occurrence and asso- 
ciations of minerals. Among his collections, those 
from the neighbourhood of Carlsbad were the most im- 
portant, but Thuringia, the Harz, and Italy were laid 
under contribution as well, ‘‘ for the mineralogist must 
be like a stag, and browse irrespective of frontiers.” 
Early in his studies Goethe felt his weakness on the 
scientific side, and to remedy it caused W. Voigt to 
be sent to Freiberg. Voigt on his return instructed 
him in nomenclature, and he began to arrange and 
label his collections, for ‘“‘every properly recorded 
observation is invaluable to posterity.’? His activity as 
a collector soon impressed on him the importance of 
good maps, and the interest thus stimulated led to the 
NO. 1937, VOL. 75 | 
gestions as to the best method of printing and colour- 
ing such maps. The colour scheme employed to-day 
is in essentials that proposed by him. 
Perhaps Goethe makes his greatest claim to be con- 
sidered a geologist by his attitude towards the problem 
of the history of the earth. Living at a time of conflict 
between Neptunists and Vulcanists, his mind was too 
well balanced to allow him to become a bigoted par- 
tisan or the slave of a hypothesis. The uniformity of 
nature was his watchword, and he neyer lost sight of 
this principle, whether discussing the erratic blocks of 
Northern Germany or the basalts of Bohemia. 
At the conclusion of his review of Goethe’s essays in 
mineralogy and geology, Prof. Linck asks the perti- 
nent question, Are such studies to be put aside with a 
smile and a shrug of the shoulders as the well-meant 
efforts of an amateur and nothing more? Prof. Linck 
thinks not. He points out that many contemporaries 
well qualified to judge thought highly of the work, and 
he holds that Goethe is justly entitled to an honour- 
able place among the pioneers in mineralogy and 
geology. We venture to think that anyone who fol- 
lows the case presented in his pages will endorse his 
verdict. 
THE CHEMICAL STRUCTURE OF 
CELLULOSE. 
Researches on Cellulose, 11. (1900-1905). By C. F. 
Cross and E. J. Bevan. Pp. xi+184. (London: 
Longmans, Green and Co.) Price 7s. 6d. net. 
N the course of their extended researches on the 
chemistry of cellulose, the authors of this work 
gradually become dissatisfied with all the 
numerous attempts which have from time to time 
been made to represent the chemical structure of this 
substance by means of ordinary constitutional 
formule. The fundamental basis for such a repre- 
sentation—the knowledge of the molecular weight— 
has always been and is still lacking, and in its 
absence the chemist has perforce limited himself to 
endeavouring to assign a chemical constitution to 
some comparatively small unit containing six, or 
some multiple of six, carbon atoms, and has usually 
regarded the complete unknown molecule of cellulose 
as a polymeride of this. A certain measure of 
success has attended these efforts, particularly as 
regards the relation of the final products of such 
processes as nitration or hydrolysis to the original 
“unite? 
The authors, however, consider all such formulz 
to be totally inadequate to express the greater 
number of the chemical changes which cellulose is 
capable of undergoing. In place of the purely 
chemical idea of cellulose as a complex polymeride 
of preformed groups of rigid configuration, they 
propose to substitute the conception of cellulose as a 
colloidal aggregate which may be considered to react 
“as a labile complex of groups of varying dimensions 
representing a state of matter somewhat analogous 
have 
