j-5 SECTION-PHYSICS. 



400, chiefly by Giuseppe Moriani, called on account of his art, " il 

 Gonna," who was famous for making thermometers of 50 perfectly- 

 similar to one another. And such do some of those existing in the 

 Royal Museum of Florence still remain. Here is a thermometer 

 divided into 470 ; and in this other one the bulb is exquisitely worked 

 so as to form a hollow branched stand full of alcohol. To render these 

 delicate thermometers less fragile here is another shape that they some- 

 times gave to the tube, by twisting it, as you see, spirally. The tube of 

 this thermometer is 230 centimetres long, and yet the total height of 

 the instrument is but 32 centimetres. Here is a thermometer on which 

 is marked the exact temperature which the water should reach in order 

 to be fit for bathing in. This one is rather a curiously shaped 

 thermometer, or thermoscope ; we owe it, also, to the Grand 

 Duke Ferdinand II.; it is described in the " Saggi dell' Accademia 

 del Cimento" as a "thermometer lazier, or more slothful than 

 the others" The tube contains alcohol, besides six little coloured 

 glass balls. At the temperature of melting ice these little balls 

 float. At 10 of their yo-grade thermometer one of the balls falls 

 to the bottom, at 20 a second one sinks, and so on. At 70 they 

 are all at the bottom. This other shape, like a small frog, used to 

 be given to similar thermoscopes, in which cases the little balls were 

 regulated so as to mark certain degrees of temperature nearer to one 

 another. The thermoscope was tied as .you see to the pulse of a 

 sick person, and served to show the intensity of the fever. In certain 

 xperiments upon the amount of heat transmitted by different sub- 

 stances which were first warmed and then plunged into water, it is 

 mentioned that of two thermometers used, the one of alcohol, the 

 other of mercury, the first to show any sign was the one with mercury. 

 It is nevertheless difficult to establish the precise date at which 

 mercury thermometers were first made. And before finishing what I 

 have to say on the subject of thermometers, I shall call to mind a 

 most useful application that was made of them even at that time by 

 the Grand Duke, that is to say, for meteorological observations. He 

 thought of availing himself for this purpose of the monks, who, 

 scattered as they were in every direction, could on account of their 

 manner of life, apply themselves better than any one else to such 

 observations. It is said that such a duty was entrusted to Padre 



