600 SEC. 14. METEOROLOGY. 



Model illustrative of the principle of the barometric gradient, which is 

 calculated by dividing the distance between any two barometers by their 

 difference in reading, both being reduced to 32 and sea level (or the same 

 level). Designed by Thomas Stevenson, C.E., Honorary Secretary, and 

 described in the Society's Journal, 1867, when the proposal was first made. 



2925. Drawing of an instrument for ascertaining sea and 

 river temperature by thermometers continuously immersed. 



Scottish Meteorological Society. 



The case containing the instruments^ suspended from the pier, or lightship 

 or in the river, and is drawn up bringing with it some water in the cistern at 

 the bottom, in which the thermometer bulbs are placed. Designed by 

 Thomas Stevenson, C.E., F.R.S.E., Honorary Secretary, and described in 

 the Society's Journal, vol. iv., p. 44. 



2926. Cloud Reflecting Compasses. For ascertaining 

 direction of higher currents of air. 



Scottish Meteorological Society. 



When a cloud is to be observed the compass should be turned round till one 

 of the hues on the mirror coincides with a well defined edge of the cloud, and 

 the compass is then made to revolve, gradually keeping the hue constantly on 

 the edge of the cloud. The angle indicated by the magnetic needle being 

 afterwards read off, the direction of the cloud's motion in azimuth is at once 

 ascertained. Designed by Thomas Stevenson, C.E., F.R.S.E., Honorary 

 Secretary, and described in the Edinburgh Philosophical Journal, 1855. 



2926a. Hypsometric Map of the Caucasus, recently 

 published by the Topographical Office at Tin 1 is. 



The Pulkowa Observatory. 



2926b. Diagrams Illustrative of Underground Tem- 

 perature. G. J. Symons. 



2927. Graphic Representations of Underground Tempera- 

 tures in Fife shire, by Sir J. Leslie. University of Edinburgh. 



2928. Graphic Representations of Underground Tempera- 

 tures near Edinburgh, by Principal Forbes. 



University of Edinburgh. 

 See Trans. Eoy. Soc. Edin., 1846, for a full account of each. 



2928a. Map of the British Isles, showing sites at which 

 rainfall observations are being made. G. J. Symons. 



2928b. Engravings of various apparatus employed in rainfall 

 experiments. G. J. Symons. 



2928d. Diagram showing the fluctuations of rainfall in central 

 England, from 1726 to 1869. G. J. Symons. 



2928e. British Rainfall. On the distribution of rain over 

 the British Isles during the year 1874, as observed at about 1,700 

 stations in Great Britain and Ireland, with maps and illustrations. 



G. J. Symons. 



