VIII. EVAPORIMETERS. 593 



2 892 a. Barometrograph. M. Breguet, Paris. 



2893. Barometer adapted to automatic registration by Pho- 

 tography. Chas. Brooke, M.A., F.R.S. 



A vertical cylinder serves (as at Greenwich) for the registration of the 

 barometer and the balanced magnetometer. See Magnetism. 



2894. Barograph. Redier, Paris. 



2895. Registering Barometer, mercurial or aneroid, show- 

 ing enlarged curves without the aid of electricity or photography. 



M. Redier. 



2895a. Registering Mercurial Thermometer, after the 

 plan of M. Herve Mangon. M. Redier. 



2896. Barograph, balance barometer ; executed by Greiner 

 and Geissler, Joint Stock Company for manufacturing meteorolo- 

 gical instruments at Berlin. 



Imperial Admiralty Hydrographical Bureau at Berlin, 

 and Deutsche Seetvarte in Hamburg. 



This instrument is put up and kept working at each of the normal observa- 

 tory stations on the German coast. The stations are subordinate to the 

 German Naval Observatory (Seewarte). 



VIII. EVAPORIMETERS. 



2897. Evaporimeter, in the form of a spring steel-yard. 

 Professor F. Osnaghi, Meteorological Central Institute, 



Vienna. 



This instrument shows on a sector the number of millimeters evaporated 

 from a certain quantity of water in a given time. As its action is produced 

 by gravity, it is also useful in winter when ice is formed on the scale. It 

 differs from other steel-yards in the weight acting on the inner end of a 

 spiral spring. 



2898. Apparatus for determining the Evaporation from 

 different soils. 



Sydney B. J. Skertchly, F.G.S., H.M. Geological Survey. 



The apparatus consists essentially of an evaporimeter composed of two 

 vessels, the innermost of which receives the material to be experimented upon, 

 and the external one supplies water to compensate for evaporation. Over this 

 is a glass vessel which receives the vapour given off by the material. The tem- 

 perature, &c., are registered by a hygrometer and barometer in the glass re- 

 ceiver, and the temperature of the soil by a ground thermometer. Any given 

 temperature can be obtained by means of a platinum spiral heated by a galvanic 

 battery. The evaporimeter maintains the material in a natural condition so 

 far as regards temperature and moisture. Dry air is admitted into the glass 

 receiver, and the air with the evaporated water passes from the top of the 

 39508. P p 



