xlviii REPORT — 18G9. 



mcnts traces ia duplicate are obtained, one set being sent to the Meteoro- 

 logical Office and one retained at Kew ; as regards the Anemograph, the 

 original records are sent, while a copy by hand of these on tracing-paper is 

 retained. The tabulations from the curves of the Kew instruments are made 

 by Messrs. Baker, Page, and Foster, 



2. Verification of liecords. — In order to maintain uniformity in the system 

 of observation at the \-arious meteorological observatories, it is arranged by 

 the Meteorological Committee that Mr. Stewart shall personally visit all the 

 observatories once every year, in addition to which, when necessary, some 

 one of the Kew assistants will occasionally visit particular stations with a 

 specific object in view. At the request of the Meteorological Committee, 

 a system of checks has been devised by the Kew Committee for testing the 

 accuracy of the observations made at the different Observatories. This system, 

 with slight modifications, is now in operation*. As this revision takes place 

 at Kew, it has been found necessary to engage an additional assistant for the 

 purjjose of undertaking it. Mr. Rigby has been engaged for this duty — Mr. 

 Baker, Meteorological Assistant, having the general superintendence of this 

 dei)artment. 



3. Occasional Assistance. — In addition to devising the system of checks 

 mentioned above, the Kew Committee have also, at the request of the 

 Meteorological Committee, examined the subject of instrumental verifica- 

 tions, and it has been found that, owing to improved construction, a higher 

 standard of excellence in meteorological instruments may be insisted upon 

 without rejecting more than a very small percentage of those furnished by 

 good makers. 



It has therefore been resolved by the Meteorological Committee that in 

 future the following limits of error shall be allowed in the construction of 

 their instruments : — 



Marine Barometers of the pattern adopted hy the Meteorological Office. — 

 Reject all for which the index-error at the ordinary pressure is greater 

 than '015 inch, or the capacity-error greater than -OO-i inch, or for which 

 the mercury does not fall from 1| inch to | inch above the present pressure 

 in a time between 3 and 6 minutes. But for barometers imrportinc/ to he 

 standards, reject all for which the index-error at the ordinary pressure is 

 greater than -010 inch. 



Thermometers {graduated on the stem) of the pattern adopted by the Meteo- 

 rological Office. — Reject all in which the largest error at any point is greater 

 than 0°-3, or in which any space of 10° is more than 0°"3 wrong. 



Hydrometers of the pattern adopted by the Meteorological Office. — Reject all 

 in which the largest error at any point is greater than 1 division of the scale 

 (equal to -001 sp. gr.), or in which any space of 10 divisions is more than 

 0-6 division wrong. 



Models of Pantagraphic Apparatus, designed by Mr. Galton, have been 

 made and experimentally used at Kew, at the desire of the Meteorological 

 Committee, to reduce the tracings of the self-registering instruments in any 

 desired proportions, either in length or in breadtli, with a view to the ulti- 

 mate publication by that Committee of all the tracings supplied by the seven 

 Observatories in a compact volume. 



It may also be mentioned, under tlie head of Occasional Assistance, that 

 at the reqiiest of the Meteorological Committee, Mr. Beckley, Mechanical 



* This scheme, having been extracted, with }3ermission, from the Report of the Meteo- 

 rological Committee, will be found in the Appendix to this Report, 



