S7i Reviews, and Notices respecting NeV) Books. 



ment in his hands would be quite as effective : he precludes the pos- 

 sibility of detecting any instrumental errors, and of increasing 

 by that means the correctness of his observations. 



We justly look with the greatest admiration at the discoveries of 

 Bradley; yet these, considered simply in the light of inequalities, 

 lie, as it vvere, at the surface of astronomical discovery. Far be it 

 from us, however, to attempt to undervalue the importance of these 

 discoveries, or the surprising ingenuity which effected them. All 

 we mean to assert is, that the merit of the discovery does not con- 

 sist in having observed these inequalities merely as inequalities, for 

 these were large in amount, and must necessarily have been detect- 

 ed by a connected series of observations with instruments of tole- 

 rable precision : but it is the explanation of the phaenomena that 

 justly demands our admiration; nor can we withhold it, when we 

 contemplate the masterly mind of Bradley, with steady and unerring 

 sagacity, disentangling the various inequalities from the mass in 

 which they were so intricately involved, and assigning to each its 

 proper cause and proper value. It is the extraordinary ability 

 displayed in the analysis, not only qualitative, but quantitative, of an 

 assemblage of most complicated physical phaenomena, that must 

 always place Bradley in the very first rank of philosophers. 



But the time is past when discoveries of this kind can be expect- 

 ed, since all the large inequalities are known by the discoveries 

 of Bradley. If others still exist, they are of a more minute de- 

 scription, which are not appreciable with certainty even by modern 

 instruments. But it is entirely with magnitudes of this almost in- 

 appreciable value that the astronomer has now to deal ; and modern 

 instruments, when used with care, seem to be sufficiently powerful 

 to estimate magnitudes of this kind with some degree of precision. 

 Until we can find materials for the construction of astronomical 

 instruments, which are not at all, or much less, affected by external 

 causes, than those now employed, we must in vain expect more ac- 

 curate divisions, or greater stability of position, than have been 

 effected by the skill of Troughton and of Jones. 



The principal object deserving attention now seems to be to 

 increase the powers of the telescopes and microscopes, while we limit 

 the magnitude of the instrument. VVe are aware that many persons 

 consider the objections to the magnitude of instruments as ground- 

 less ; but we are convinced that no person who has been accustomed 

 to the use of instruments, will look upon them in this light. Next 

 to this our attention should be directed to use modern instruments 

 so as to do full justice to the great powers they possess ; but this, 

 as has been observed, requires the greatest skill and the most at- 

 tentive and delicate treatment. The want of a comprehensive de- 

 tail of instructions for this purpose has long been felt by young 

 astronomers; and this want has never been supplied until Dr. Pear- 

 son, with unbounded industr)-, and the greatest liberality in the ex- 

 penditure both of money and time, has furnished a work, which in 

 our opinion is fully adecjuate to the object he had in view. 



It is only, however, from a careful perusal of the work itself, to 



