45, COBNH1LL, E.G., AND 122, REGENT STREET, W., LONDON. 



41 



FIG. 47. 



FIG. 46. 



FIG. 45. 



ground. Suggested and recommended by the Rev. F. W. Stow, who advises 

 that the bulb end of the thermometer should be placed facing the S.E., and in 

 such a manner that the air may circulate freely round it. Strict shade 

 temperature should also be noted by a good Thermometer, so as to obtain 

 the Maximum in sun and shade, and from these the amount of Solar Radiation 

 may be deduced. Fig. 45. Price, 110 



54. Fig. 46 shows a new arrangement of Negretti and Zambra's Patent 

 Solar Radiation Maximum Thermometer in vacuo. It will be seen in the 

 woodcut that the bulb of the Thermometer is exposed to the sky in a vertical 

 position, with its stem enclosed by a light case or box. The scale is on the 

 stem of the Thermometer, but, as in No. 57 the scale is figured the reverse 

 of an ordinary instrument, the reading commencing from the end of the tube 

 and not at the bulb. This arrangement has been introduced by N. and Z. to 

 meet some requirements in connection with observations on solar temperatures 

 where it has been supposed that a perfect sphere presented to the solar rays 

 would give far more accurate indications than a projecting bulb such 'as 

 seen in figs. 41 and 43. Fig. 46. Price, 1 15 



55. Negretti and Zambra's Patent Registering Clinical 

 Thermometers of various sizes and forms will be described in future sections 

 with prices and illustrations. 



56. Babinet's Apparatus, Sling Thermometer or Thermometer Fronde, 

 for ascertaining the temperature of the Air by the rapid rotation of two sensitive 

 Thermometers, Price with Thermometers. (Fig. 47.) 2 10s. 



