OF NATURAL PHILOSOPHY- 133 



when strongly illuminated by the setting sun, viewed 

 through a doubly refracting prism. 



(128.) To avail ourselves as far as possible of the 

 advantages which a division of labour may afford 

 lor the collection of facts, by the industry and ac- 

 tivity which the general diffusion of information, in 

 the present age, brings into exercise, is an object of 

 great importance. There is scarcely any well- 

 informed person, who, if he has but the will, has 

 not also the power to add something essential to 

 the general stock of knowledge, if he will only 

 observe regularly and methodically some particular 

 class of facts which may most excite his attention, 

 or which his situation may best enable him to study 

 with effect. To instance one or two subjects, 

 which can only be effectually improved by the 

 united observations of great numbers widely dis- 

 persed: Meteorology, one of the most compli- 

 cated but important branches of science, is at 

 the same time one in which any person who will 

 attend to plain rules, and bestow the necessary 

 degree of attention, may do effectual service. 

 What benefits has not Geology reaped from the 

 activity of industrious individuals, who, setting aside 

 all theoretical views, have been content to exercise 

 the useful and highly entertaining occupation of 

 collecting specimens from the countries which they 

 visit? In short, there is no branch of science what- 

 ever in which, at least, if useful and sensible 

 queries were distinctly proposed, an immense mass 

 of valuable information might not be collected from 

 those who, in their various lines of life, at home or 

 abroad, stationary or in travel, would gladly avail 

 K 3 



