The salmon placed in this inclosure had to be carted in tanks of water overland about a mile in addition to transportation in floating cars from 3 to 5 miles; they were transferred suddenly from the salt water of the river (about two-thirds as salt as common sea-water) into the entirely fresh water of the lake.  To all the supposed unfavorable circumstances must be added the high summer temperature of the water.  During August the mean was generally above 70 degrees Fahrenheit at the bottom and several degrees warmer at the surface.  Occasionally there was observed a midday temperature of 74 degrees F. and once 75 degrees at the bottom.  Yet this proved an excellent place for our purpose, a satisfactory percentage of the salmon remaining in perfect health from June to November.

No. 4.  The inclosure in use since 1870 at Dead Brook, Bucksport.  It is located in a gently running stream bordered by marshy ground, with a bottom in part of gravel but mostly of mud, crowded with aquatic vegetation.  The water, supplied by two small lakes among the hills, is cleaner than the average of Maine rivers, but does not in that respect approach the water of inclosure No. 1.  The greatest depth is about 8 feet, but in the greater part of the inclosure it is from 3 to 5 feet.  The width of the stream is from 2 to 4 rods, and the portion inclosed is 2,200 feet long.  The barriers to retain the fish are in the form of wooden gratings, with facilities for speedily clearing them of debris brought down by the stream.

Better results were expected from this inclosure than from No. 3, but have not been realized.  The percentage of salmon dying in confinement has been greater, amounting commonly to about 25 percent of those introduced, and this notwithstanding the salmon are conveyed to the inclosure by water carriage the entire distance (7 miles) instead of being carted in tanks.

The cause of the trouble has not yet been discovered, but there is good reason for thinking that it lies in some of the circumstances attending the transfer of the fish from the place of capture, and that the inclosure itself is perfectly suited to its purpose.  This view is supported by the fact that nearly all the losses occur within a few weeks after the introduction of the salmon and almost wholly cease by the end of July.  If the cause of disease was located in the inclosure, we should expect it to be more fatal after a long than a short duration of the exposure of the fish to its action, and that with the smaller volume and higher temperature of August it would be more active than in June and July.

The above description will, I think, give Dr. Bottemanne a sufficiently correct idea of the character of the inclosures we have tried.  There are, however, several other points to be touched upon to put him in possession of the practical results of our experience.