Form No, 55. 2M-3-'i5. 



THE COMMONWEALTH OF MASSACHUSETTS. 



JOHN R. RABLIN, 



METROPOLITAN PARK COMMISSION, 



ENGINEERING DEPARTMENT, 



14 Beacon Street, 



Boston, June 22, 1915. 



Mr . Walter Deane , 



Sherburne, f, H. 



Dear Sir: 



In reply to your inquiries of June 18th, I would say 

 that the information in regard to chlorine in the water of the 

 Charles River Basin was probably from analyses taken at different 

 seasons of the year, and if you could examine the records of all 

 analyses you would find that the quantity varies from practically 

 nothing in the spring to from 100 to 200 parts in 100,000 in the fall. 

 This variation is due to the fact that the fresh water flow of the 

 river during the winter flushes out the river and keeps it fresh 

 until such time as the lack of fresh water from above allows the 

 amount of salt water to increase. 



The salt water entering the Basin from the operation of 

 the locks, being much heavier than the fresh water, is likely to 

 affect the water of practically the whole Basin, especially in 

 dry seasons, but remains at the bottom of the river. 



The elevation 0.64 below mean low water is Boston city 

 ^ base. The elevation which you saw on an old map at City Hall, 



Cambridge, referred to Cambridge city base, which is 4.98 feet 

 below mean low water. 



If at any time you desire to examine the records of the 



