112 Extract of Letter from Mr. Chambers, Bombay. [Apr. 26, 



porarily accorded to me by the Bombay Government, by my appointment 

 to the superintendence of this Observatory. The confirmation of my pre- 

 sent appointment will probably depend upon the sanction of the scheme 

 of improvements for the Observatory which I have just sent in for the 

 consideration of Government. Meanwhile I have arranged the working 

 power of the establishment so as to take up the reduction of the old obser- 

 vations, and I am sure you will be interested to learn that there is a pro- 

 bability of their turning out trustworthy and valuable. The separation of 

 seven years of declination-disturbances has already been effected, with the 

 results shown in the enclosed Tables and Curves ; but as the whole series 

 of observations (from 1845 to 1865) will include two complete cycles of 

 the decennial period, and as the reductions have already been so long 

 delayed, I propose completing the twenty-one years before discussing the 

 connected questions and publishing the whole ; it is, however, a little 

 doubtful whether the opportunity of doing this will be afforded me, as 

 the Indian Government, in sanctioning my appointment, have limited its 

 duration to the end of next month ; and though I am hopeful that, partly 

 in consequence of a representation that I have made to the Government, of 

 the wide scope for usefulness that is open to me here, and of what has 

 been effected and has been engaged upon since my arrival six months 

 ago, they may be induced to extend their approval of the appointment 

 until the improvements suggested in my Report shall have been consi- 

 dered, yet it seems right, as there are some interesting points about the 

 results already arrived at, that I should inform you of them whilst I may, 

 especially as in case of a second reference of the matter to the home 

 Government, you will, I believe, consider them good grounds upon which 

 to recommend the continuance of the reductions of the twenty-one con- 

 secutive years of the Bombay observations. 



Referring to page 283 of your paper in the Philosophical Transactions, 

 1863, it will be seen that these results supply the required knowledge of the 

 laws of the disturbances at a station intermediate in longitude between Kew 

 and Nertschinsk. The general characteristics of the westerly disturbance- 

 diurnal-variation curve are the same as you describe for Pekin and Nerts- 

 chinsk. The curve is remarkably regular, and the ordinates between 

 8 P.M. and 4 a.m. have scarcely appreciable values, being in the latter 

 respect like the westerly curve for Hobarton, and the easterly for Kew 

 and St. Helena. The maximum occurs at 11 a.m., which corresponds 

 to about ] 8*" Kew astronomical time, implying, by comparison with the 

 corresponding hours of maximum at the other two eastern stations (Pekin 

 and Nertschinsk), a rather slow propagation of the disturbing action from 

 north to south of the eastern part of the northern hemisphere. The other 

 curve (of easterly disturbance) presents a less systematic appearance ; and 

 the ratios are at no part of the day smaller than 0*64, or greater than 

 1-83. 



