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The following are statistics of counts taken in 1909 at the different bridges:

TABLE No. 2

Location of Count	Period covered by count	No. of vessels passing
Sixth Street Bridge	Aug. 24 - Oct. 23 (61 days)	4,534
Ninth Street Bridge	Aug. 26 - Sept. 30 (36 days)	3,279
Fort Wayne Bridge	Aug. 20 - Oct. 28 (70 days)	4,925
Thirtieth Street Bridge	Aug. 24 - Oct. 23 (61 days)	2,022
J. R. R. Bridge	Sept. 13 - Nov. 13 (60 days)	1,460
Forty-third Street Bridge	Aug. 23 - Nov. 1 (70 days)	1,580

Assuming that the ratio between the number of vessels during any given period and the total for the year is the same at all bridges as at Dam No. 1; and assuming that the relative number of different kinds of vessels are the same at all bridges; and further assuming that the average weight of cargo is the same at all bridges as recorded at Dam No.1, we reach the estimates of total traffic under the bridges given in Table No. 3.

FOR THE YEAR 1909 -- TABLE No. 3

Location of count	No. of vessels	*Weight of vessels	Weight of cargoes	*Wt. of vessels and cargoes
Sixth Street Bridge	21,763	1,097,378	1,247,020	2,344,398
Ninth Street Bridge	25,904	1,311,823	1,484,299	2,796,122
Fort Wayne Bridge	20,685	1,043,020	1,185,250	2,228,270
Thirtieth Street Bridge	9,706	489,416	556,154	1,045,570
J. R. R. Bridge	8,030	404,905	460,199	865,024
Forty-third Street Bridge	6,636	334,613	380,243	714,856

*The following data as to weight of vessels was kindly furnished by Mr. J. F. Tilley:

WEIGHTS OF RIVER CRAFT WITHOUT FREIGHT

Medium tows	800 tons
Pool Tows	175 tons
Barges	55 tons
Coal boats	105 tons
Flats	30 tons
In estimating we assumed the following average weights for river craft based in large measure upon the above data
Steamboats	225 tons
Coal boats and barges	80 tons
Barges	55 tons
House boats, excursion boats, yachts, and U. S. Government boats	45 tons
Launches, skiffs, etc	45 tons
Motor boats and miscellaneous	10 tons

The largest total, that passing under the Ninth Street bridge, is without doubt somewhat less than the total traffic on the river,

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Last modified on 22-Dec 1999
Design format: copyright 1997-1999 Bruce S. Cridlebaugh
Original document: Frederick Law Olmsted, 1910