3«4 



NATURE 



[■[anuary 4, lyij 



D' 



l.lQl'jn CRYSTALS.^ \ The tendency during iho past i,,ri> or fifty 



kURING the seven years that have t-Iapsed since | was for active workers in science to become six* 

 the publication, in uk>4. o^ his previous book, j i.e. to confine th«'ir attention wholly to one? or t 

 entitlrti '• Kliissit^'e Kristallr." Prof. I^hmann has in i small compartments, and to pay little or no heed 



what is btrinjf done by others in c< 

 ti^uous compartments'; the most stri 

 inj{ feature, on the other hand, 

 recent development of science is li 

 revelation it has afforded of the ir 

 interdependence subsisting !»• 

 the so-called branches of it. i 

 eminently true of crystallocraj/ 

 lonj; regarded only in if« 

 aspect as an adjunct of i 

 in its specific aspect of i. 

 it is already recognised as of coriMtl 

 able importance to the chemist ;i 

 prtrologist, and now Prof. L«l 

 tells us that crystals are potent 

 in the processes of life, and th«Ti:' 

 that they fc)rm a subject with whi- 

 biologists should be cognisant. 



The field of research into whii 

 Prof. Lehmann struck out nearly fc>i 

 years ago was then so utterly i. 

 known and yielded such ama/ing i 

 suits that it is no matter for surpri 

 if his early reports were received wi: 

 the scepticism usually accorded to 

 travellers' tales. His observations 

 were set down as optical illusioi^ 

 and his conclusions vigorously coi 

 bated, but the passage of time \. 

 gradually brought about a chan^^ 

 and at the present day most of th( 

 who have given any serious study 

 the subject are in general agreemem 

 with him ; for instance. Prof. Wal- 

 lerant, the eminent French crystallo- 

 grapher, has remarked, " I^ d^ou- 

 verte de M. Lehmann est certaine- 

 nient une des plus importantes du 

 si^cle dernier; ses consequencf< vont 



Fig. i.-CrysulliMtuon-microscope with camera attachment. nombreuses et de premier 



no way abated his energy, and has poured out a con- i 

 stant stream of papers giving the results of, and the 

 deductions from, further observations, so that another 

 or at least a supplementary work is already called for. 

 Prof. Lehmann decided to write an entirely new book, 

 which, being complete in itself, would readily enable 

 any reader interested in the subject to learn what 

 has been done in it and what is the present situation. 

 The subject is not easily understood, and most of tlv 

 experiments upon which it is founded cannot be per- 

 formed without special apparatus. It has so far 

 received scanty attention in this country, and its ex- 

 treme importance is perhaps not fully realised. Out- 

 side Germany Prof. Lehmann has given demonstra- 

 tions before the Mineralogisch-Petrographische Gesell- 

 schaft in Vienna, and the Socii^te Fran<;aise lit 

 Phvsique in Paris; may we not hope that some societ\ 

 in this country will be sufficiently enterprising to 

 induce Prof. Lehmann to give a similar demonstration 

 in London? No one who has witnessed these beau- 

 tiful phenomena can fail to agree in the main with 

 Prof. Lehmann's conclusions; to see is to believe, 

 and. as Pro^. Lehmann says (p. 5). "jeder, welchtr 

 Gelegenheit hatte die Versuche zu sehen, sich da von 

 iiberzeugte, die Erscheinungen konnten unmoglich 

 anders gedeutet werden." 



' "Die neue Welt der flussigen Kristalle und deren Bedeutung fiir 

 Physik, Chemie, Technik und Biologic." By Dr. O. Lehmann. Pp. vii + 

 ?f8. (Leipzig; Akademische VerUgsgesellschaft m.b.H., 191 1.) Price 12 

 m.vks. 





NO. 2201, VOL. 88] 



tiC. 2.— Liquid crystals between crosse„ 



