1901.] Observations at the Valencia Observatory. 247 



Seeing that no use was being made of these observations, and 

 Trinity College requiring their instruments, Professor FitzGerald came 

 to the conclusion to terminate the work, and the observations accord- 

 ingly ceased. Soon after enquiries were made for them, and very 

 strong expression of their value given, with a desire for their continu- 

 ance. Acting on such weighty opinion, he determined to put the 

 observations on a business and permanent basis by obtaining a set of 

 modern instruments, and a fund to endow the work. Enough was 

 collected in Ireland to ensure the observer a small annual honorarium. 



With a new set of instruments, examined at Kew Observatory, the 

 present series of observations was commenced in January, 1899, in the 

 original wooden observing house erected in the field north of the 

 Observatory, 90 yards from that building. A railway runs east and 

 west about 50 yards north of the hut, and five light trains pass each 

 way daily, but these do not appear to materially affect the magnets 

 whilst observing. The observing house being copper-fastened, with no 

 iron down-pipe, this is the only magnetic interference likely to affect 

 the results. 



In determining the position of the hut, consideration was given to 

 obtaining a satisfactory fixed mark, visible from the observing pillar, 

 and the down-pipe of a school house about 1 mile north of the 

 Observatory was decided upon, as being the property of the Board of 

 Works and likely to be permanent. Not having the means of obtain- 

 ing sufficiently accurate time for a sun's transit, the orientation of this 

 mark was determined by taking three series of observations of equal 

 altitudes of the sun by means of a transit theodolite lent by Kew 

 Observatory for the purpose ; the mean of these was taken, and the 

 value 19° 46' 0" W. used in the reduction of the declination observa- 

 tions. 



The observatory is situated on an arm of Valencia Harbour, co. 

 Kerry, lat. 51° 56' N., long. 10° 15' W., and is consequently about the 

 most western part of the United Kingdom. 



The unifilar is by Dover, No. 139, and, as before stated, was verified 

 at Kew Observatory, where the constants of the magnet were also 

 determined, and tables of corrections supplied in the usual manner 



The dip circle is also by Dover, No. 118 ; it was also examined and 

 passed at Kew. 



For the convenience of observing, the two middle days of each 

 month have been adhered to throughout ; the declination being 

 observed about 10 A.M. Greenwich (local time 41 mins. later), the 

 actual mean time for the three years being 10.9 A.M. 



The mean time of the inclination observations is for the morning 

 11.45 a.m., and for the afternoon 1.25 p.m., these being made on 

 succeeding days with two needles, which . give unusually consistent 

 results, the mean of each of the three years showing an excess in No. 1 



