492 ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



the aspiratory power of the flame. With a very narrow 

 burner, and great velocity, no flame can be produced. The 

 spectrum, with compressed gas, is discontinuous, showing five 

 bright lines; with slow efliux, the spectrum is continuous; in 

 the first case the combustion being more complete, and in the 

 latter there beins: more unconsumed solid carbon. These ob- 

 servations, the author thinks, should be taken into account 

 in lighting cities with great difierence of level (as in Lisbon, 

 where it amounts to over 300 feet), the jets in the higher por- 

 tions approximating those of compressed gas in character ; 

 and in order to produce the same illumination as in the low- 

 er portions, from the same gasometer, the cocks should be 

 less widely opened. 14 (7, CCVIIL, 1873, 156. 



RELATIOX OF THE AIR TO CLOTHING AND SOIL. 



The following statements of general interest are specially 

 reliable, being contained in a lecture by Professor Pettenko- 

 fer, of Munich, who is known as high authority on such sub- 

 jects; Although the warmth of the body is the result of res- 

 piration, it is a singular fact that the normal temperature of 

 the blood of the African is the same as that of the Esquimau, 

 or about 99^, while the air surrounding them, and inhaled 

 by them, may differ as much as 180 in temperature; neither 

 does this temperature vary, in a state of health, more than 

 two degrees, though the temperature of the air may vary 72. 

 The heat generated by the human body in twenty-four hours 

 is sufficient to raise tliirty quarts of cold water to the boil- 

 ing-point; and of this the regular processes of nutrition 

 require only a definite part, and the larger portion must 

 be given off" through radiation, evaporation, or conduction. 

 When heat is lost by radiation, as in sitting near a cold 

 window, or other cold object, the impression of a draught 

 may be created, although the air be perfectly calm, heat be- 

 ing simply given up to the colder object. Thus, while the 

 temperature of a room may remain constant, different sensa- 

 tions may be experienced, dependent on the surrounding ob- 

 jects. A much larger amount of the superffuous heat is lost 

 by evaporation ; and during severe exercise, when more heat 

 is developed, evaporation is also more rapid, and the normal 

 temperature of the blood restored. A "cold" is caught when 

 the evaporation is too rapid. But little heat is lost by con- 



