X. MISCELLANEOUS. 723 



2938. Thermometer Screen for meteorological stations of the 

 2nd order. In use at the stations of the Norway Meteorological 

 Institute. Prof. ff. Mohn, Christiania. 



Made of plate iron. To be mounted outside a window and kept in shade. 

 The screen contains one psychrometer (dry and wet bulb), one minimum 

 thermometer (both instruments made by R. Grave in Stockholm), and one 

 hair-hygrometer (made by Herman and Pfister in Bern). The screen is 

 constructed after the designs of Prof. H. Mohn. 



2939. Thermometer Screen for one single thermometer for 

 obtaining the temperature of the air. In use at stations belonging 

 to the Norway Meteorological Institute. 



Prof. H. Mohn, Christiania. 



Made of plate iron. To be mounted outside a window or on a wall, and kept 

 in shade. With thermometer, made by E. Grave, in Stockholm. Screen 

 constructed after the design of Prof. H. Mohn. 



2940. Thermometer Screen for one minimum thermometer. 

 In use at stations belonging to the Norway Meteorological Insti- 

 tute. Prof. H. Mohn, Christiania. 



Made of plate iron, with double walls. Suspended on a cylindrical rod 

 intended to pass through the window-frame. The rod has a handle inside, so 

 that the screen with the thermometer can be turned for " setting " in the same 

 way as a thermograph. The double walls prevent the rising of the ther- 

 mometer, even in direct sunshine, to more than a few degrees above the 

 temperature of the air. The minimum thermometer is made by K. Grave, in 

 Stockholm. The screen is executed after designs of Prof. H. Mohn. 



2941. Stevenson's Box for Thermometers. 



Scottish Meteorological Society. 



The box is louvre-boarded, and painted white inside and outside, and 

 screwed to four stout posts, also painted white, firmly fixed in the ground. 

 The posts must be of such a length that when the thermometers are hung in 

 position the bulbs of the minimum thermometer, and of the dry and wet bulb 

 thermometers, will be exactly at the same height of 4 feet above the ground, 

 the maximum thermometer being hung immediately above the minimum 

 thermometer. The thermometer box is to be placed over a plot of grass, and 

 in a free open space to which the sun's rays have free access during as much 

 of the day as surrounding conditions enable the observer to secure. The 

 thermometers are suspended on cross-laths in the centre of the box, and face 

 the door, which should open to the north. 



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

 described in the Society's Journal, vol. i., p. 122. 



2942. Plunging Apparatus, by " Baudin/' for observations 

 at sea, with maxima air-bubble thermometer of " Walferden," and 

 minima vertical thermometer of " Baudin," withdrawn from ex- 

 ternal pressure. M. Baudin, Paris. 



2942a. Model, illustrative of Meteorological Sections of the 

 atmosphere. Scottish Meteorological Society. 



Showing vertical gradient for temperature, pressure, humidity, &c., ascer- 

 tained by dividing the difference of readings between the instruments at the 



Z z 2 



