994 THERMOMETER 



sion of the degrees of one scale into those of another, comparative tables, which how- 

 ever, convey no information beyond the bare fact of the correspondence of certain 

 degrees. In this table, the attempt has been made to make it convey information on 

 numerous interesting points, connected -with temperature in relation to climatology, 

 physical geography, chemistry, and physiology. 



There is another advantage which a table of this kind must possess over those 

 hitherto published in works on chemistry. In the latter, the degrees on one scale 

 only run in arithmetical progression, while the corresponding degrees on the other 

 scale are necessarily given in fractional or decimal parts, and at unequal intervals. 

 Thus, in some of the best works on chemistry, a comparative table is printed, which 

 is only fitted for the conversion of the Centigrade into Fahrenheit degrees, so that a 

 person wishing to convert the Fahrenheit into Centigrade degrees, would have to 

 revert to one of the old formulae of conversion. This process must also be adopted 

 whenever the Centigrade degrees are given in decimal parts, for many of the tables 

 published in English works wrongly assume that the Centigrade degrees are always 

 given in whole numbers. The present table renders such calculations unnecessary, 

 since the value of any degree, or of any part of a degree on one scale, is immediately 

 found on the other, by looking at the degree in a parallel line with it. The main 

 divisions will, it is believed, be found perfectly accurate. In single degrees a little 

 inequality may be occasionally detected; but the error has not been found to be such 

 as to affect the calculated temperature. 



Although the Fahrenheit and Centigrade scales are the two which are chiefly 

 used in Europe, it has been thought advisable to carry out the parallel degrees of 

 Keaumur's scale, by dots on the drawing of the tube. This table, therefore, com- 

 prises in itself six distinct tables, assuming the necessity for each scale to be repre- 

 sented in whole degrees, with the additional advantages : 1st, that the space occupied 

 is smaller ; and 2nd, the value of any fractional part of a degree on one may be at 

 once determined on the other two scales. 



It is extraordinary, considering the great advances which have been recently made 

 in physical science, and in the manufacture of philosophical instruments, that the 

 makers of thermometers should still adhere to the old and absurd practice of mark- 

 ing on the Fahrenheit scale, the unmeaning words Temperate, Summer-heat, Blood- 

 heat, Fever-heat, Spirits boil, &c., when the instrument might be easily made to 

 convey a large amount of information in respect to climate, as it is dependent on 

 temperature. 



It will be seen that the table here published ranges from 12 to 374 Fahrenheit., 

 from 11 to + 190 Centigrade, and from 9 to + 152 Keaumur. 



It will be only necessary to state generally those facts which the table is intended 

 to illustrate. They will be found arranged opposite to their respective degrees, either 

 on the Centigrade or Fahrenheit side, according to the space afforded. 



The facts connected with temperature placed on the scale may be arranged under 

 the heads of Climatology, Physical Geography, Chemistry, and Physiology. 



Climatology. 1. The mean temperatures of the principal countries, towns, and 

 cities in the world, with the maxima and minima, as well as the mean summer and 

 winter temperature of some of the most important localities. 



2. The maximum degrees of heat and the minimum degrees of cold observed on 

 the surface of the globe, including the accumulated temperatures of air at Edinburgh 

 and Geneva. 



Physical Geography. 1. The temperature ot the atmosphere, as observed on the 

 summits of the principal mountains of the Old and New World, with the respective 

 elevations attached ; at the sea-level in various latitudes, from the Arctic to the 

 Antarctic Seas, as well as in deep mines and other excavations in Europe and America. 



2. The temperature of the ocean at the surface, and at various depths to 12,420 feet, 

 including the temperature of the Polar Seas, of the Mediterranean, Atlantic and 

 Pacific, with the temperature of the Gulf Stream. 



3. The temperature of the waters of lakes and rivers at various depths, with the 

 respective fathomings attached. 



4. The temperature of the strata of the earth at various depths, observed in some 

 of the deepest mines in the Old and New World. 



5. The temperature of the water raised in Artesian wells in Europe from depths 

 varying from 250 to 1,794 feet. 



6. The temperature of the principal thermal springs and baths observed in Europe, 

 Africa, the West Indies, and South America. 



7. The temperature at which water boils at all the elevated and inhabited spots in 

 the world, including the summits of the mountains of Switzerland, South America, and 

 Central Asia ; the boiling point for all elevations up to 5,415 feet, and for 1,054 feet 

 depression below the level of the sea. 



