QS2 Natural History, [Chap. IH, 



others, to whom due honour is given by various 

 writers on the subject. The vohimes of viemolrs 

 published by the scientific academies, indifferent 

 parts of Europe, during the century under review, 

 contain rich treasures of meteorological informa- 

 tion, contributed by numerous hands. 



Modern times have given birth to various in- 

 ventions for measuring the force and velocity of 

 winds. Among these, the most remarkable are the 

 Wind-gage, the Anemoscope, and the Ane7nometer ; 

 m the construction and improvement of which 

 Dr. Linn, Mr. Pickering, and others, have rendered 

 important service to meteorology. Numerous at- 

 tempts have also been made, during the period 

 imder review, to construct liygrometers, or instru- 

 ments for indicating the comparative states of the 

 atmosphere with respect to moisture and chnjness. 

 And though mucli imperfection is found to attend 

 every instrument hitherto devised for this pin-pose, 

 }ct gradual approximations have been made to- 

 ward those of a more perfect and useful kind. 

 Among these, Mr. Smeaton's hygrometer, ioxvciQ([ of 

 a hempen cord boiled in salt water ; M. de Saus- 

 sure's, made of human hair prepared by macera- 

 tion in alkaline ley; Mr. Coventry^'s, consisting 

 of dried paper ; and M. de Luc's, of ivory and 

 zvhalcbone ; deserve to be distinguished : especially 

 that formed of zohalehone by M. de Luc, which is 

 genera! {y considered as the most accurate and con- 

 venient hygrometer now in use. 



That remarkable meteorological phenomenon 

 usually called tlic Aurora Borealis appeared Avith 

 pevuliar frequency in the course of the eightecntl^ 



