38 PROCEEDINGS MANCHESTER INSTITUTE 



courtesy of Gordon Woodbury, Esq. On Mr. Woodbury's 

 estate in Bedford there is an artificial pond, which, a centur}^ 

 and a half ago, supplied power for a sawmill, but which for 

 many years has been retained for pleasure only. This pond, 

 having originally an area of about five and one-half acres, is 

 formed by damming Cold Brook, a stream of considerable vol- 

 umt and great activity, which flows sinuously down a valley of 

 its own making through an extensive forest from the sand plains 

 and low hills beyond. This brook, in the long period since the 

 first construction of the dam, by bringing down sand from 

 the plains, and debris from the woodland, had filled fully two- 

 thirds of the original area of the pond and greatly lessened 

 the depth of the remaining portion. 



Mr. Woodbury decided upon an extensive excavation, and in 

 August of the present year the contractor began operations. 

 The work was completed in November ; silt and miscellaneous 

 detritus of an average depth of three feet and ten inches having 

 been removed from an area of five and one-half acres. The 

 excavation was so thorough that, with the exception of a 

 small island upon which shrubs and trees were left standing, 

 there was not a vestige of plant or animal life in the entire area. 

 The gate was closed on November 21, and three days later wa- 

 ter began flowing over the dam. 



Mr. Woodbury having previously expressed a readiness to 

 co-operate in any investigations that might be undertaken, the 

 Council of the Institute requested Mr. Frederick W. Batchelder 

 to make a stud};- of the return of aquatic plants to this area, 

 while the present writer was similarly requested to make care- 

 ful observations and report upon the progress of the natural 

 restocking of the pond with animal life. 



On December 21, one month from the closing of the gate, the 

 first formal investigation was made, with the assistance of George 

 E. Burnham, Secretary of the Entomological Section of the In- 

 stitute. Insects had ceased flying before the excavation was 

 completed in November, and there were but two ways open bj^ 

 which aquatic life could find entrance to the pond — one by the 

 brook, and the other from a marsh of some extent, which had 



