PREFACE. 



nature : like that extraordinary work, they 

 are at once the amusement of childhood 

 and ignorance, and the delight, instruction, 

 and admiration, of the highest and most 

 cultivated minds. 



It is not, however, to be supposed, that 

 theory and observation alone will enable 

 us to judge either of pictures or of nature, 

 with the same skill as those, who join to 

 the practical knowledge of their art, habi- 

 tual reflection on its principles, and its 

 productions ; between such artists, and the 

 mere lover of painting, there will always 

 be a sufficient difference to justify, the 

 remark of Cicero :* but by means of the 



* There is an anecdote of Salvator Rosa, which shews 

 the very just and natural opinion that painters of eminence 

 entertain of their superior judgment with regard to their 

 own art: it is also highly characteristic of the lively, 

 impetuous manner of the artist of whom it is related, and 

 whose words might no less justly be applied to real ob- 



