173 UPLAND AKD MEADOW. 



" make a night of it," if necessary, to see the crayfish at 

 work. Placing a candle, with a mirror behind it, at a 

 convenient point, he succeeded in getting a light upon 

 the chiamey about equal to that of the full moon, and 

 he himself remained in shadow. After the lapse of 

 some minutes, in perfect silence, my nephew saw the 

 antennae of the crayfish above the opening of the bur- 

 row. These were waved in the air, as if to scent or in 

 some way recognize danger; for experiment showed 

 that the slightest noise caused the crayfish to fall back 

 into his burrow "like a lump of lead." An interim of 

 fully five minutes elapsed, when the crayfish reappeared. 

 Nothing disturbing it, the animal half-emerged into 

 view, and brought on the back of its right claw a ball 

 of clay-mud, which, by a dexterous tilt of the claw, was 

 placed on the rim of the chimney. Then the crayfish 

 remained perfectly quiet for a few seconds, when it 

 suddenly " doubled up " and dropped to the bottom of 

 its burrow. There elapsed some three or four minutes 

 between each appearance; but every time it came it 

 brought a ball of clay and deposited it in the manner I 

 have described. About two fifths of the balls were not 

 placed with sufiicient care and rolled down the outside 

 of the chimney. If all crayfish work as deliberately as 

 did this one observed by my nephew, then the chim- 

 neys are not built in one night; but of this fact, how- 

 ever, I am so positive, that the crayfish that was seen at 

 work was certainly an exception to the rule. 



It being known that these chimneys are designed, and 

 how they are made, let some one add an important item 

 to the world's common stock of knowledge by telling it 



