if necessary, of other pursuits.  Still the question has not unfrequently presented itself to me, whether the duties to which I allude have not, by force of circumstances, become too exclusive; and whether the cause of Science might not gain if, as in the Imperial Observatory of Paris for instance, the higher branches of mathematical physics should not take their place by the side of Observatory routine.  I have often felt the desire practically to refresh my acquaintance with what were once favourite subjects:  Lunar Theory and Physical Optics.  But I do not at present clearly see how I can enter upon them with that degree of freedom of thought which is necessary for success in abstruse investigations.”

Of private history:  There was a longer visit than usual to Playford, lasting till Jan. 27th.—­In April he made a short excursion (of less than a week) with his son Hubert to Monmouth, &c.—­From June 14th to July 2nd he was staying at Barrow House, near Keswick, with his son Hubert:  during this time he was much troubled with a painful skin-irritation of his leg and back, which lasted in some degree for a long time afterwards.—­From Sept. 25th to Oct. 6th he made an excursion with his daughter Christabel to Scarborough, Whitby, &c., and again spent a few days at Barrow House.

1871

“In April 1870 the Assistants had applied for an increase of salary, a request which I had urged strongly upon the Admiralty.  On Jan. 27 of this year the Admiralty answered that, on account of Mr Childers’s illness, the consideration must be deferred to next year!  The Assistants wrote bitterly to me:  and with my sanction they wrote to the First Lord.  On Jan. 31st I requested an interview with Mr Baxter (secretary of the Admiralty), and saw him on Feb. 3rd, when I obtained his consent to an addition of L530.  There was still a difficulty with the Treasury, but on June 27th the liberal scale was allowed.—­Experiments made by Mr Stone shew clearly that a local elevation, like that of the Royal Observatory on the hill of Greenwich Park, has no tendency to diminish the effect of railway tremors.—­The correction for level error in the Transit Circle having become inconveniently large, a sheet of very thin paper, 1/270 inch in thickness, was placed under the eastern Y, which was raised from its bed for the purpose.  The mean annual value of the level-error appears to be now sensibly zero.—­As the siege and war operations in Paris seriously interfered with the observations of small planets made at the Paris Observatory, observations of them were continued at Greenwich throughout each entire lunation during the investment of the city.—­The new Water-Telescope has been got into working order, and performs most satisfactorily.  Observations of gamma Draconis have been made with it, when the star passed between 20h and 17h, with some observations for adjustment at a still more advanced time.  As the astronomical latitude of the place of observation is not known, the bearing of these