Dr. Pearson's Introduction to Practical Astronomy. 451 



This volume is dedicated to the Astronomical Society of London, 

 of which Dr. Pearson was for ten years the treasurer ; and he has 

 taken this opportunity of showing his high sense of the honour con- 

 ferred upon him, by dedicating to its members in general this collec- 

 tion of Tables, so well calculated to promote the objects for which 

 the Society was instituted. 



" Some opinion may be formed of the extent of the author s la- 

 bours, when it is stated, that, of the ^S? pages constituting this 

 volume, 325 contain new Tables, or explanatory matter ; 46 are 

 filled with Tables that have been enlarged, or otherwise improved; 

 and 86 only comprise Tables that have been copied in their original 

 state." , 



The first set of Tables contains the corrections to be applied to 

 the apparent place of a star, in order to obtain its place clear from 

 the effects of 7-i°/rcrci;w«. 



The first four Tables are computed from the formula ol bradley; 

 and as the explanation given of their use is quite clear, we need say 

 no more about them. The Tables of Refraction next in order are 

 those published in 1806 by the French Board of Longitude : these, 

 as our author informs us, are founded on the profound investigations 

 of La Place. But whether the most elaborate formula deduced by 

 this eminent geometrician is more to be depended on than that 

 given by Bradlev, may perhaps be questioned. The arrangement 

 given by our author is that adopted at Greenwich. The next set 

 of Tables for this purpose are those computed by Stephen Groom- 

 bridge, Esq., who conducted a long series of observations for this 

 purpose, with one of the most peifect meridian instruments that was 

 ever constructed. We allude to the beautiful transit circle made 

 by Troughton, and which is fully described by our author in his 

 second volume.— The Tables next in orderare Piazzis: these were 

 constructed without any reference to theory, and were deduced from 

 observations made out of the meridian. 



Among those who have laboured in this interesting department of 

 science, the late Dublin astronomer, Dr. Brinkley , must not be passed 

 over. Our author has introduced the Tables computed by this 

 acute philosopher, and thev deserve notice, inasmuch as the for- 

 mula on which they depend is original, and displays the greatest 

 ingenuity We refer our readers to the original papers m the Irish 

 Transactions, as they are most peculiarly interesting and "istruc- 

 live We also refer to the account and explanation of these labies 

 given by our author.— The late Dr. Young, whose penetration was 

 so remarkable that few things passed under his observation without 

 undergoing some improvement, also investigated a formula for re- 

 fraction. Our author informs us that the Tables computed from 

 this formula are said to agree more exactly with the latest observa- 

 tions than any others. . , ,. • i i t> 



The Tables following ire constructed by the indefatigable bes- 



scl Our author's account of them is as follows : " He has mvcsti- 



-ated the subject of Refraction, and, retainmg the characters of 



La Place, has deduced the following formula, on which he calcu- 



3 M2 



