1915] Deane,— A Salt Marsh during Reclamation 207 
water, and before the next run of high tides the fill was made nearly 
complete. There has been no appreciable movement of the structure 
since the filling has been in progress." 
Mr. Hiram Allen Miller, consulting engineer for the Commission, 
writes under date of June 5, 1913, “ The permanent level of the Basin 
is at grade 8 and it rarely ever varies 2 or 3 inches above or below that 
elevation. There is no appreciable current in the year below the 
arsenal, except in case of heavy floods." The arsenal is at North 
Beacon Bridge referred to later. Mr. George Lyman Rogers, Secre- 
tary of the Commission, writes under date of May 16, 1913, “ In answer 
to your inquiry relative to the freshness of the water in Charles River 
Basin opposite Cambridge Cemetery, I would say that an average 
of fifteen analyses made of the water in the Basin at Western Avenue 
Bridge in 1912 showed 32 parts chlorine in every 100,000 on the sur- 
face, and on the bottom 54 parts chlorine to 100,000. This is practi- 
cally fresh water. "The analyses at North Beacon Dridge made even a 
better showing," and Mr. John R. Rablin, engineer of the Commis- 
sion, writes me on June 5, 1915, “ The following table from the chemi- 
cal examination of water in the Charles River Basin, taken at West 
Boston and North Beacon Street bridges in 1914, shows the number 
of par:s in 100,000 of chlorine: 
West Boston Bridge, Surface, July, 35.00; Oct. 174.00 
+ $ i Bottom, “ 65.50  * 168.00 
North Beacon St. Bridge, Surface, “ 1.60 — * 140.00 
É ü i * "Bottom, ." 1.50  " 143.00." 
In regard to the discrepancy between these figures and those given 
me by Mr. Rogers, Mr. Rablin writes on June 22, 1915, “In reply to 
your inquiries of June 18, 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 [rom 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 :t fresh until such time as the lack of fresh water from above 
allows the amount of salt water to increase." In the same letter he 
writes, “The salt water entering the Basin from the operation of the 
locks, being much heavier than the fresh water, is likely to affect 
