EXPERIMENT STATION REPORTS. 179 



Assistant Professor Mallmann has continued in charge of the analysis of 

 rural water supplies. We have taken advantage of the Quarterly to give in- 

 structions relative to the collection of water samples. His report follows: 



During the past year, this laboratory has tested 106 samples of water. 

 Fifty-seven of these samples were sent in from rural districts and represented, 

 in practically every case, farm wells. Fifty per cent of these samples showed 

 pollution, according to the standards adopted by the U. S. treasury depart- 

 ment and were reported as unfit for domestic use. 



An effort is always made to help the farmer improve his water supply and 

 in several cases, where the farmer followed our directions, the cause of the 

 pollution was removed and the water made safe for domestic use. 



Beginning last year, we have required that a full history of each well, 

 accompany the sample. We required this because we believed we could 

 judge a sample more accurately and further, we could give more assistance 

 with less correspondence. The questionnaire has been of greater value than 

 we even anticipated. It has given us the opportunity to judge tl>e water by 

 considering all probable sources of pollution and thus allowing us to give more 

 advise as a means of improving the supj^ly. 



Besides testing all samples of water submitted to us, we have also kept 

 close watch on the College and East Lansing water supplies. Both of these 

 supplies are deep wells and have shown no signs of pollution during recent 

 years. 



Examinations of the College swimming pool have been made also twice a 

 week. During the fall term, a daily test was made to determine the extent 

 of pollution and the best means of controlling it. A further study will be made 

 this coming fall. At present the water is purified by filtration and chlorina- 

 ated lime. The chlorinated lime is added at the rate of 13 pounds per million 

 gallons of water twdce a week. The use of chlorinated lime is not very satis- 

 factory and it is recommended that a liquid chlorinator be installed. This 

 form of chlorination has proved satisfactory wherever installed and the cost 

 of installation is comparatively low. 



[W. A. Mailman.] 



Research Assistant Snyder has pushed the work with the nodule-forming 

 bacteria with carefulness and vigor. He will have charge of the soil investi- 

 gations (Adams 2c) next year and Frank Davenport (Mass. Agr. College, '21) 

 will look after the pure culture distribution. 



Dr. Snyder's report follows: 



