--On Mar, 26th I went to Reading, to visit Mr Sheepshanks, and
afterwards to Silchester and Hereford.--On June 21st I went with my
wife and two eldest sons to Edinburgh and other places in Scotland,
but residing principally at Oban, where I hired a house. Amongst other
expeditions, I and my son Wilfrid went with the 'Pharos' (Northern
Lights Steamer) to the Skerry Vohr Lighthouse, &c. I also visited
Newcastle, &c., and returned to Greenwich on Aug. 2nd.--From Oct. 12th
to 17th I was at Cambridge.--On Dec. 24th I went to Playford."
CHAPTER VII.
AT GREENWICH OBSERVATORY--1856 TO 1866.
1856
"In the Report to the Visitors there is an interesting account of the
difficulties experienced with the Reflex Zenith Tube in consequence of
the tremors of the quicksilver transmitted through the ground.
Attempts were made to reduce the tremor by supporting the
quicksilver trough on a stage founded at a depth of 10 feet below the
surface, but it was not in the smallest degree diminished, and the
Report states that 'The experience of this investigation justifies me
in believing that no practicable depth of trench prevents the
propagation of tremor when the soil is like that of Greenwich Hill, a
gravel, in all places very hard, and in some, cemented to the
consistency of rock.
Pages:
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372