The Rôle of Liquid Crystals in Nature

Abstract

THIRTY-SIX years have elapsed since Prof. Otto Lehmann, while a student at Stuttgart, designed a novel form of microscope which permitted of the optical examination of substances at temperatures differing considerably from that of the surrounding air, and thus obtained access to an almost virgin field for research, to the cultivation of which he has strenuously devoted himself. The results of a long series of observations were collected and published in the form of the fine volume entitled “Flüssige Krystalle,” which was noticed in NATURE in 1904 (vol. Ixx., p. 622). Prof. Lehmann, however, by no means intended that work to constitute his last word on the subject, and, as is testified by the numerous papers which have since that date appeared from his pen in various journals, he has in no way relaxed his efforts in the prosecution of his investigations. Of recent years, moreover, other workers have in greater number been attracted to the subject, and their observations are, on the whole, in harmony with his, and confirm the substantial correctness of the views he has put forward. In particular, mention may be made of Prof. D. Vorländer's extensive investigations of the azoxy-compounds. Although there was in early days, not unnaturally, considerable scepticism regarding the correctness of Prof. Lehmann's observations and the deductions he made from them, there is at the present time little reason to doubt the reality of the existence of anisotropic liquids and the importance of the rôle they play.