Author: SAUSSURE, HORACE BÉNÉDICT DE
Title: Essais sur l'Hygrométrie. Ier. Essai. Description d'un nouvel Hygrometre comparable. II. Théorie de l'hygrométrie. III. Théorie de l'évaporation. IV. Application des théories ... météorologie. AND 2) IDEM, Défense de l'Hygrometre a cheveu, pour servir de suite aux essais sur l'hygrométrie.
Description: Neufchatel, Geneve & Paris, Samuel Fauche [vol. I], Barde, Manget & Comp., Buisson, 1783. - 1788. 2 vols. W. woodc. vigns., engr. head piece in vol. I, 2 engr. pls. (1 fold.).; vol. 2 engr. vign. on title, woodc. head piece, 1 engr. single page plate at the end. Both vols. in (early 20th c.) private .... red mor., spines and turn ins with gilttooled floral ornaments or single rule. Covers of 1783 vol. w. 2 single rules and single giltt. rose in corners; covers vol. 1788 w. single rule. (Some sl. dam. to 1 corner.). (The bindings near uniform, spine vol. I some discol.). (XXIV, 367, I (blank); IV 60, II (Table and 'Avis') pp.). (Pp. 105 - 116 of vol. I w. vague grayish spots surrounding the textblock; a few spots here and there; Vol 2 clean and fresh.). First edition of the 'Essais' and first book edition of the 'Défense'. DSB vol. XII, pp. 119 - 123: '... [De Saussure] was strongly influenced by two naturalists, his uncle Charles Bonnet and the physician Albrecht von Haller. ... Saussure's dedicated work was of great importance in the development of geology, since, among other things, it provided James Hutton with fundamental documentation. In addition Saussure devised a number of useful instruments, among them a hair hygrometer that utilized a degreased human hair to measure humidity, and he also performed some experiments on the fusion of granites and porphyries that entitled him to be considered the first experimental petrologist. Finally, he popularized the very term "geology", which replaced "geognosy" in the 1770's and 1780's.': The human hair hygrometer [volume 2 1788 here offered] was first described in "Observations sur la physique", 1788, pp. 24 - 45, 98 - 107. It appeared separately in Geneva 1788.: Daumas, scient. instr. pp. 215/6: ' ... infinitely more complex and delicate, is the research of H.-B. de Saussure, on hygrometry. ... In about 1775 de Luc and de Saussure were both working independently on the same problem. De Luc invented a mercury hygrometer in which the hygroscopic element was an ivory tube; ... His first attempts were unsuccesful, but in the course of the following years, de Saussure perfected his hair hygrometer and studied its working and graduation; In Geneva the instrument-maker Paul constructed it in the form it was to retain. De Saussure's studies were sufficiently precise and complete for his instrument to find favour, and its readings were considered to be constant until the time of Regnault.': Wolf, Hist. of science, p. 326: 'Cuvier regarded de Saussure's Essays as one of the greatest contributions made to science in the course of the 18th century.': Sparrow, Milestones, pp. 26/7, item 174 (Plate 110), the "Essais" 1783 only: 'The first edition of "Essais ..." (1783) records his experiments with the hair hygrometer and his investigations on the theory of evaporation and hygrometry and their applications to meteorology (plate 110).': Turner, Early scientific instr., pp. 255 - 275: '... one of the leading naturalists of his day. He was a pioneer of scientific alpinism, and his important and innovative researches in geology, natural history and meteorology were all related to the study of mountainous areas, ...':

Keywords: hygrometers W60