68 



Mr. R. H. Scott. 



A system was organized for etching a " Hall-mark," as in the 

 annexed figure, upon all Thermometers which have been 



verified. 



The Astronomer Royal having courteously offered the Committee 

 every facility for a suggested comparison between the Greenwich and 

 Kew Standard Barometers during April and May, a number of care- 

 fully selected Portable Standard Barometers were conveyed to and fro 

 between Greenwich and Kew on three separate occasions, and a large 

 number of comparative readings were obtained by the Superintendent 

 and Messrs. Baker and Foster. 



A complete detailed account of the experiment was drawn up, 

 and laid before the Royal Society, February 7th, 1878. (Proceedings, 

 Vol. XXVII, p. 76.) 



A Hydraulic Press especially constructed for the purpose of sub- 

 jecting Deep Sea Thermometers to pressures similar to those they 

 experience when sunk to great depths, was erected in the workshop. 

 Tt is capable of exerting a strain equal to 4 tons on the square inch. 



1879. Experiments were commenced at the Observatory, with the 

 view of determining the relative merits of different patterns of 

 thermometer screens, and continued for upwards of two years. For 

 this purpose there were erected on the lawn a Stevenson's screen, 

 of the ordinary pattern, and a large wooden cage, enclosing a Wild's 

 screen, of the pattern employed in Russia. Each of these screens 

 contained a dry and a wet bulb thermometer, and a maximum and 

 minimum, all of which were read daily, at 9 a.m. and 9 p.m., their 

 indications being compared with those of the thermograph at the 

 same hours. 



A discussion of the twenty-eight months' observations was sub- 

 sequently made by Mr. Whipple, and the results jDublished by the 

 Meteorological Council. 



1880. A Sub- Committee, which had been appointed in 1878 to 

 consider the best means of utilising the records of the magnetographs, 

 reported that it was inadvisable, in their opinion, to proceed with the 

 regular tabulation of the curves, and suggested that attention should 

 rather be directed to their comparison with synchronous curves, taken 

 at other Magnetic Observatories in different parts of the globe, in 

 order to ascertain whether similar disturbances occur at these several 

 stations, and at what time intervals ; with a view to the development 

 of the theory of magnetic disturbance. 



In order to carry out this scheme, a circular, inviting co-operation 

 on the part of observers provided with magnetographs of the Kew 

 pattern, was issued to the Directors of the following Observatories : — 

 Batavia, Bombay, Brussels, Coimbra, Colaba, Lisbon, Mauritius, 

 Melbourne, Potsdam, St. Petersburg (Pawlowsk), San Fernando, 

 Stony hurst, Utrecht, Vienna, and Zi-Ka-Wei. Replies favourable to 



