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ANNUAL REPORT SMITHSONIAN INSTITUTION^ 1915. 



Other early workers were Eoger Bacon, an English Franciscan 

 monk, who died in 1294; Solomon de Caiix (1576-1626), a French 

 engineer, who, in 1615, invented and described the first machine for 

 raising water by solar heat and the expansion of air; Ducarla; and 

 H. B. de Saiissure, the Swiss geologist, physicist, and naturalist, who 

 made (in 1787) the second ascent of Mont Blanc. To de Saussm^e the 

 credit is due for inventing the " hot box " (i. e., an insulated air-tight 

 wooden box, black inside, and covered with two laj^ers of plain glass 

 with an air space between them) , which has since been such a favorite 

 with other workers. It was he, too, who found that a cover of two 

 sheets of glass gave the best results. 



Next in the field was Sir John Herschel, F. E. S., who in 1837 took 

 the temperature of the surface soil near Cape Town, and for dry earth 

 recorded temperatures varying from 120° F. to 162° F., the latter 

 having been obtained on December 1, 1837, at 0.36 p. m., in a sand heap 

 sheltered from the wind in a small garden inclosure, the soil being 

 moist 3 inches or 4 inches below the surface. 



He also experimented Avith a " small mahogany box, blackened 

 inside, covered with windowglass fitted to size, but without putty, 

 and simply exposed perpendicularly to the sun's rays." In this box 

 he recorded a temperature of 152° F., but " when sand was heaped 

 around the box to cut off the contact of cold air, the temperature 

 rose on December 3, 1837, to 177° F. And when the same box, with 

 its inclosed thermometer, was established under an external frame of 

 wood well sanded up at the sides, and protected by a sheet of win- 

 dowglass (in addition to that of the box within), the temperatures 

 attained on December 3, 1837, were — 



and that with a steady breeze sweeping over the spot of exposure. 

 Again, on December 5, under a similar form of exposure, tempera- 

 tures were observed : 



As those temperatures far surpass that of boiling water, some amusing experi- 

 ments were made by exposing eggs, fruit, meat, and in the same manner (Dec, 



