No. 55 438. 



Thermometers. Recording Instruments. Actinometers. 



651 



55 437. 1 : 5. 



55438. 1:10. 



s. d. 



55.426. Spring Thermometer, Figure 0. 10. 



The maximum system thermometer is divided iu 1 / 6 from 10" to + 100" C. and has a pro- 

 tecting ring for the mercury bulb, the latter being provided with a tuft of hair for holding the spring 

 water. 



55.427. Baro-Thermograph, Figure, combined recording instrument for air-pressure and 

 temperature, in walnut case 12. 10. 



55.428. --idem, in aluminium casing 15. 0. 



55.429. Baro-Hygrograph, in walnut case 13. 0. 



55.430. Baro-Psychograph 15. 0. 



55.431. Thermo-Hygrograph 12. 10. 



55.432. Baro-Hygro-Thermograph 18. 0. 



All recording instruments are also supplied in a metal casing at the same price. 



55, -133. Statoscope for observing the ascent and descent of a balloon, model of the Eoyal 



Aeronautical Batallion 4. 10. 



55.434. Aneroid Barograph, one rotation of drum in 12 hours, with leather case, straps and 



rifle hook 7. 10. 



55.435. Solar Radiation Thermometer, Figure, on stand 1. 4. 



The mercury vessel is surrounded by an evacuated bulb; the thermometer is provided with 

 maximum device, being graduated fiom 10 to + 70 C. in l /z- 



55.436. - - Two of the preceding, without stand, in case 1. 16. 



The bulb of one thermometer is blackened, the other plain. 



55.437. Pair of Bulbs after Violle, Figure, for measuring solar 'radiation 4. 0. 



Of the two bulbs, consist ing <>f thin sheet copper, one is dull black on the outside, the other 

 polished and gilded; both bulbs are jet black internally. Each carries a thermometer divided in 1 / t ". 



55.438. Actinometer after Violle, Figure, recording, with two scribing levers writing 



on drums .31. 10. 



Two thermometers are, together with their sensitive vessels, enclosed in metal spheres, one of 

 the latter being polished and the other jet black. 



Cl. 1973, 

 1974.3429. 



