REPORT OF THE CHEMIST. 



145 



the direct rays of the sun and that of the air with a similar exposure. 

 Three observations were made each day, as given below. 



The soil was a sandy loam, of a light-gray color, resting on a com- 

 pact clay subsoil at the depth of twelve inches. It was well pulverized 

 to the extent of eight or ten inches deep. We regret that no oppor- 

 tunity ofiered to vary these experiments in different varieties of soils 

 and under different circumstances. The observatious were continued 

 through a week, commencing on the 13th of August, 1872. The bulb 

 of the thermometer was placed live inches below the surface. 



It will be seen from these observations that the difference between 

 the air and the soil is least in the morning, attains its maximum at noon, 

 and maintains substantially the same relations till 3 p. m. To reach any 

 reliable conclusion, however, these experiments should be repeated at 

 different seasons of the year, and in several varieties of soils. It is an 

 interesting field of research, and one which we hope those who have 

 opportunity will not fail to occupy. 



The subject of 



THE WASTES QF CITIES AND TOWNS 



was referred to this division for investigation, and, as far as time and 

 opportunity would permit, that investigation has been prosecuted by a 

 pretty thorough examination of the various reports made from time to 

 time on the sewage of the great cities of Europe and America, and its 

 effect on rivers, springs, and other streams of water. In addition to 

 this we have opened a correspondence with parties on both sides of the 

 Atlantic, from which much important information has been obtained. 

 The subject is one of greater magnitude than has heretofore been ap- 

 prehended ; and its importance is not by any means limited to its sani- 

 tary relations, though these constitute an imx)ortant phase of the 

 subject. 



The investigations developing the laws of health and the general 

 advancement of sanitary science in the last half-century have created a 

 lively interest in the subject of the best method of disposing of excre- 

 ment, garbage, and other refuse matter from cities, towns, and manu- 

 factories. The habit of hiding such waste matter in rivers so polluted 

 many of the waters of England as to call for a remedy from the govern- 

 ment. In,1855, by a royal warrant, a commission was created to inquire 

 into the extent of this river-i)ollution, and to suggest a remedy. In 1868 

 this commission was revoked and a new one issued with enlarged pow- 

 ers. This commission ha^ made four very full reports, from which we 

 learn something of the alarming extent to which the rivers of England 

 10 A 



