AUTHOR'S PREFACE. xiii 



etudy of nature (consisting in animated delineations, land- 

 scape painting, and the arrangement and cultivation of 

 exotic vegetable forms), of the history of the contemplation of 

 the universe, or the gradual development of the reciprocal 

 action of natural forces constituting one natural whole ; and 

 lastly, of the special branches of the several departments of 

 science, whose mutual connection is indicated in the begin- 

 ning of the work. Wherever it has been possible to do so I 

 have adduced the authorities from whence I derived my facts, 

 with a view of affording testimony both to the accuracy of my 

 statements and to the value of the observations to which refer- 

 ence was made. In those instances where I have quoted from 

 my own writings (the facts contained in which being, from 

 their very nature, scattered through different portions of my 

 works), I have always referred to the original editions, owing 

 to the importance of accuracy with regard to numerical re- 

 lations, and to my own distrust of the care and correct- 

 ness of translators. In the few cases where I have extracted 

 short passages from the works of my friends, I have indicated 

 them by marks of quotation; and, in imitation of the practice 

 of the ancients, I have invariably preferred the repetition of 

 the same words to any arbitrary substitution of my own 

 paraphrases. The much contested question of priority of 

 claim to a first discovery, which it is so dangerous to treat of 

 in a work of this xincontroversial kind, has rarely been 

 touched upon. Where I have occasionally referred to clas- 

 sical antiquity, and to that happy period of transition which 

 has rendered the sixteenth and seventeenth centuries so cele- 

 brated, owing to the great geographical discoveries by which 

 the age was characterised, I have been simply led to adopt 

 this mode of treatment, from the desire we experience from 

 time to time, when considering the general views of nature, 

 to escape from the circle of more strictly dogmatical modern 

 opinions and enter the free and fanciful domain of earlier 

 presentiments. 



