PROCEEDINGS OF THE POLYTECHNIC ASSOCIATION. G15 



American Institute Polytechnic Association 

 3Iarch 24. 1864 



i 



' Chairman, Prof. S. D. Tillman; Secretary, Mr. B. Garvey. " 



During the hour devoted to the examination of new inventions and dis- 

 coveries, the Chairman read the following interesting summary: 



Bodily Work and Waste. 



Under this title, the Popular Science Beview illustrates the great trutli, 

 established by modern research, that every manifestation of physical force 

 involves the metamorphosis of a certain quantity of matter. Its facts 

 regarding the daily work performed by the ordinary human being are 

 chiefly furnished by the investigations of the Rev. Prof Haughton, of 

 Trinity College, Dublin, who asserts that there is a definite relation between 

 the amount of force exerted and the amount of urea generated. The urea 

 formed daily in a healthy man, weighing 150 pounds, fluctuates fn;m 400 

 to 650 grains. Of this 300 grains are the result of vital work; that is, of 

 force expended in the motions of the digestive organs and the heart, and 

 jn sustaining the temperature of the body at a uniform rate. This amount 

 exceeds all other force generated and expended in the system, and is equal 

 to that required to raise 769 tons one foot high. In addition to the mere 

 act of living, the working man undergoes bodily labor equivalent to lifting 

 200 tons one foot high daily, which requires the formation of 77.38 grains 

 of urea. The force expended in two hours hard mental labor involves an 

 expenditure of power equal to lifting 222 foot tons, and a generation of 

 urea weighing 86 grains. Thus we have the total formation of urea during 

 twenty-four hours amounting to 463.38 grains, for which there is expended 

 force equal to 1,191 foot tons. 



The Chairman added: Urea is a colorless substance which by slow evapo- 

 ration crystalizes in four-sided prisms. It consists of two atoms of carbon, 

 two of nitrogen, two of oxygen and four of hydrogen. Its rational for- 

 mula has not been definitely settled. A little more than forty-six per cent 

 by weight consists of nitrogen. It is through this important compound 

 that nearly all the" nitrogen of the exhausted tissues of the body are re- 

 moved. According to Becquercl, there is an excess of urea formed in the 

 male sex in the ratio of 17 to 15. Although the amount depends somewhat 

 on the nature of the food, Lehmann discovered long ago that strong exer- 

 cise of the bodily powers increased its excretion. Urea was first made 

 artificially from inorganic substances by Woliler. By the addition of two 

 atoms of water, urea is changed to the carbonate of ammonia, and thus 

 becomes a valuable fertilizer. 



Soluble Blue Dyes. 



Mauve and other color compounds of the aniline class obtained from coal 

 tar are but slightly soluble in water. M. Clavel has patented in France a 

 process for rendering them more soluble. lie dissolves the dye in forming 

 sulphuric acid, and then pours the solution into water, through which a 

 current of steam is passed. It is then precipitated by an alkali or common 

 salt. The coloring matter, which collects in flocculi, is washed and dis- 

 solved in boiling water, and is then ready to be used in dyeing. 



