Jui.Y 6, IfWJ.] 



SCIENCE, 



(Veigbt-tiain ahead, may he regarded as of 

 great importance to the American railroad 

 system, in a manner crowning the edilice, and 

 enabling roads to be operated with greater 

 speed, safety, and regularity, 



( To be continued.) 



THE INFLUENCE OF GRAVITATION, 

 MOISTURE, AND LIGHT UPON THE 

 DIRECTION OF GROWTH IN THE 

 ROOT AND STEM OF PLANTS. 



'Members of my present botany class have 

 perforiped some experiments this spring, bear- 

 ing upon the above caption, wiiich, although 

 not developing any thing new in the interest 

 of the extension of experimental methods in 

 the lower schools, it seems to me may be 

 found worthy of a record in the columns of 

 Science, 



Seven balls of moss, about four inches in 

 diameter, were prepared, in the centre of which 

 were planted fioni fifty to a hundred grains of 

 oats, barlej', or corn ; in some cases a mix- 

 ture of two of these grains. 



No. 1 was suspended in free air. lighted on 

 all sides. No. 2 was placed on a glass tum- 

 bler, in the bottom of which some water was 

 kept, but not enough to rise within two inches 

 of the lowest part of the ball. No. 3 was fit> 

 ted into the mouth of an inverted bell-glass in 

 such a manner that one half of the ball was 

 within the jar and one half without it. No. 4 

 was placed one half within and one half without 

 a bell-glass placed in a horizontal attitude. 

 No. 5 was in a tight tin can, the ball fitting 

 it like a stopjier, so as to exclude the light 

 and to prevent a circulation of air. One-half 

 of the ball protruded from the can, and the 

 can was inverted. No. O was placed in a 

 can similar to that of no. 5 ; but this was 

 placed in a horizontal attitude, as in no. 4. 

 No. 7 was mounted upon a spindle running 

 through its centre. The spindle was attached 

 to the stem of the minute-hand of an eight-daj- 

 clock in such a manner that the axis of the 

 spindle was a continuation of the axis bearing 

 the minute-hand of the clock. The spindle 

 was a piece of one-eighth inch brass wire hav- 

 ing a strip of tin soldered to one end of it. 

 The tin was perforated with a square hole, 

 exactly fitting the shaft of the minute-hand of 

 the clock. The other end of the wire was 

 filed down to form a small journal, which worked 

 in a hole bored in a lump of solder secured to 

 the end of a wire which acted as a support to 

 the distant end of the spir.dle. This supporting 

 wire was first bent double, forming a narrow 



V, and the solder, which served as a box for the 

 Journal, dropped in the vertex. The two arms 

 of the V were then bent upon themselves in the 

 same direction so as to form a right angle with 

 the plane of the V. Two holes were bored in 

 the frame of the clock above the dial, but close 

 to it. and the arms of the bent V inserted. The 

 minute-hand was then removed from the clock, 

 and .ilso the washer behind it. The tin shoul- 

 der of the spindle was then placed upon the 

 shaft, and tiic minute-hand replaced ; the 

 shoulder serving in the place of the washer, 

 which hail not been replaced. It was only 

 necessary- to shorten the pendulum a little to 

 enable the clock to record time with its usual 

 regularity. 



The results observed after germination were 

 as follows : — 



In no. 1 the stems all came out in a clump 

 at the top of the ball, and the roots in a cluster 

 from the under side. The roots, however, 

 after protruding from half an inch to an inch, 

 curved upon themselves, and re-entered the ball, 

 or else withered. In no. 2 the stems all came 

 out at the top, and the roots at the bottom ; but 

 the roots in this case continued straight down- 

 ward into the water, no one of them turning 

 back into the ball. In no. 3 the plants de- 

 ported themselves in all respects as those did 

 in no. 1, except that the growth was very much 

 more rapid. In no. 4 all of the stems except 

 two came out of the ball into free air : two 

 grew horizontally' into the bell-jar. A large 

 cluster of the roots came out of the ball and 

 entered the jar, and continued to grow horizon- 

 tally, only depending so much as was neces- 

 sary b3- their own weight. Others of tiie roots 

 emerged from the lower side of the outer half 

 of the ball, but soon entered it .igain. In no. .5 

 all of the stems came up in the dark, damp 

 atmosphere ; and the roots emerged from the 

 lower side of the hall, but re-entered it again, or 

 else perished. Many of the stems (oats in this 

 case) threw out a pair of opposite bodies, ap- 

 parently secondar\- rootlets, which grew hori- 

 zontall}-, in all cases observed, to a length of 

 about one inch. The color of the stems in 

 this case was a pale yellow. In no. all of 

 the stems came from the ball upward into the 

 light, and very many of the roots protruded 

 horizontally into the can, some of them leav- 

 ing tiie ball above its centre, A corn-root 

 extended itself hoinzontally four inches beyond 

 the surface of the ball, and in that distance 

 wa^ only depressed one-half of an inch. On the 

 corn-roots back of the sensitive tips, the deli- 

 vatc root-hairs were so numerous and long as 

 to give it a resemblance to the hair-brush for 



