SPIRAL TWINERS.

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stick, and was steadily revolving. I then took a longer stick andtied up the shoot, so that only a very young internode, If of aninch in length, was left free; this was so nearly upright that itsrevolution could not he easily observed; but it certainly moved,and the side of the internode which was at one tune convex be-came concave, which, as we shall hereafter see, is a sure sign ofthe revolving movement. I will assume that it made at least onerevolution during the first twenty-four hours. Early the nextmorning its position wa3 marked, and it made the second revolu-tion in 9 h.; during the latter part of this revolution it moved muchquicker, and the third circle was performed in the evening in alittle over 3 h. As on the succeeding morning I found that theshoot revolved in 2 h. 45 m., it must have made during the nightfour revolutions, each at the average rate of a little over 3 h. Ishould add that the temperature of the room varied only a little.The shoot had now grown 34- inches in length, and carried at itsextremity a young internode 1 inch in length, which showed slightchanges in its curvature. The next or ninth revolution waseffected in 2 h. 30 m. From this time forward, the revolutions wereeasily observed. The thirty-sixth revolution was performed atthe usual rate ; so was the last or thirty-seventh, but it was notquite completed ; for the internode abruptly became upright, and,after moving to the centre, remained motionless. I tied a weightto its upper end, so as to slightly bow it, and thus to detect anymovement; but there was none. Some time before the last revo-lution the lower part of the internode had ceased to move.

A few more remarks will complete all that need be said on thisone internode. It moved during five days; but the more rapidmovement after the third revolution lasted during three days andtwenty hours. The regular revolutions, from the ninth to thirty-sixth inclusive, were performed at the average rate of 2 h. 31m.: theweather was cold; and this affected the temperature of the room,especially during the night, and consequently retarded a littlethe rate of movement. There was only one irregular movement,when a segment of a circle was rapidly performed (not counted inthe above enumeration) ; and this occurred after an unusually slowrevolution of 2 h. 49 m. After the seventeenth revolution the inter-node had grown from If to 6 inches in length, and carried an inter-node li inch long, which was just perceptibly moving; and thiscarried a very minute ultimate internode. After the twenty-firstrevolution, the penultimate internode was 2g inches long, andprobably revolved in a period of about three hours. At the

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