10 



L. CASELLA'S CATALOGUE 



FIG. 47. 



FIG. 30*. 



45. Earth Thermometer, for ascertaining the temperature below the soil, or the heat 



developed in hay-stacks, pine and melon pits, etc., with pointed copper 

 tube, from (according to length) . . ' . . 18 6 



46. MAXIMUM AND MINIMUM THEBMOMETEBS ; the pair, in a neat pocket mahogany 



case for travellers, as arranged for Dr. Livingstone and Captains Burton and 

 Speke. They are divided on the stem, and cannot be injured in travelling, 

 unless by actual breakage ..... 2 2 



47. Maximum and Minimum Thermometers, of smaller size, as specially designed 



by L. CASELLA for the Alpine Club, and for use at sea ; very portable, and 

 admirably adapted for travelling invalids (fig. 47) . ' '.. - 150 



In these improved portable maximum thermometers, the index will not shift its position by 

 disturbance, or in unsteady situations, as on shipboard, etc., whilst the instrument may be used 

 either erect, inverted, or in any other position, and is certainly the most portable, and of more 

 extended application than any other registering thermometer, whether it be in meteorological 

 observations, or in physical or clinical researches. 



Directions. To set the index of Maximum Thermometers Nos. 46 and 47, bring it to its 

 place with a moderate swing of the arm, keeping the bulb down at the time. This will bring it 

 within about a degree of the rest of the mercury, at which point also it shows the existing 

 temperature, the reading being taken from the end furthest from the bulb. To set the 

 TTniTiimnni index of Nos. 46 and 47, raise the bulb as No. 39. It may then be either laid down 

 or suspended, as convenient, with the bulb kept a little lower than the opposite end. 



Directions for Using the Spirit Minimum Thermometer, No. 39, etc. Suspend it by 

 the loops, or lay it down with the bulb a good half inch lower than the opposite end ; and, to set 

 the thermometer disengage the bulb end, and raise it up until the index flows to its place in 



