90 Personal Equation. 



recommend at about £200. The examination would consist 

 of soundings around the entrance and the channels of the 

 lakes and the bars of the rivers, borings to learn the nature 

 of the strata at the entrance, guaging of the several rivers 

 and the entrance to the lakes, together with a series of tidal 

 observations, and the set of the currents and prevailing 

 winds. 



28. Trusting that you will approve of my course of action 

 on this matter, 



I have the honor to be, Sir, your obedient servant, 



Thomas E. Rawlinson, Road Engineer. 



Note. — Since my report on the lake entrance was submitted, the report 

 of the District Surveyor on the same subject has been published, and I beg 

 to call attention to its general tenor and statements. 



Although written by a gentleman who bas evident sympathies in favour 

 of the feasibilities of the lake entrance, I think an impartial reader will 

 perceive that the facts and admissions contained therein are nearly all more 

 or less in support of the views which I have advanced on the subject. 



Seeing that I have not the means of submitting the surveyor's report for 

 the information of the members, I feel that it would be unfair to extend my 

 comments on the same beyond tbis note. 



The opinions advanced by me in the preceding report as to the difficulties 

 and dangers of the entrance, are borne out by the recently issued report of 

 the Chief Harbour Master, Capt. Ferguson. 



17th Jan. 1865. T. E. R. 



Since the date of the report three sailing vessels have been lost and two 

 steamers have been banked in. T. E. R. 



Art. XXIII. — On the Determination of Personal Equation 

 in Astronomical Observing. By Robert L. J. Ellery, 

 Esq., F.R.A.S., Government Astronomer. 



[Abstract of a paper read 2nd November, 1863.] 



This was a short paper read principally to describe a small 

 apparatus devised by Mr. Ellery for the purpose of obtaining 

 the personal equation of different observers under conditions, 

 as far as possible, similar to those under which the usual 

 astronomical observations are made. It consists of an 

 artificial star made to move across the field of view of the 

 transit instrument at about the rate of an equatorial star, 

 and to give a galvanic signal, on the chronograph apparatus, 

 at the instant its position -corresponds with the centre wire 

 of the Micrometer, the observer also making a signal at the 

 instant he observed the star to cross it. The difference of 

 time, as shown on the chronograph, obtained for each 

 observer, gives the means of ascertaining the personal 



