Stridulation

“ The principal effort required in flight is, therefore, made during extension, and at the beginning of the down stroke. The elastic ligaments are variously formed, and the amount of contraction which they undergo is in all cases accurately adapted to the size and form of the wing, and the rapidity with which it is worked; the contraction being greatest in the short-winged and heavy-bodied insects and birds, and least in the light-bodied and ample-winged ones, particularly such as skim or glide. ”

“ In the deep sleep that had come upon the crawler, arms and legs kept raising in a deliberate, dreadful climbing motion. It was as though they had a life of their own—they kept their movement independently of the motionless body. ”

“ Thirdly, climbing plants, like other plants, bend towards the light by a movement closely analogous to that incurvation which causes them to revolve. This similarity in the nature of the movement was well seen when climbing plants were kept in a room, and their first movements in the morning towards the light, and their subsequent revolving movements, were traced on a bell-glass. We have also seen that the movement of a revolving shoot, and in some cases of a tendril, is retarded or accelerated in travelling from or to the light. ”

“ Unconsciously he feels with his feet; they come to know the exact time to move, whether a long or short stride be desirable, and where to put down, not to rustle or cause a cracking sound, and accommodate themselves to the slope of the ground, touching it and holding it like hands. ”

“ By stride we mean the movement that covers the ground from the time a certain foot comes to the ground until it is again planted. Through moment photography we have gained a knowledge, not only in every phase of the ordinary paces of the horse, but practically of every movement the animal is capable of making; and through the same medium I was able to explain, for the first time, the gallop changes, which very important movement was previously not understood, and was procured only by tentative experiments with each horse trained to make it. ”

“ When a revolving shoot strikes a stick, it winds round it rather more slowly than it revolves. For instance, a shoot of the Ceropegia, revolved in 6 hrs., but took 9 hrs. 30 m. to make one complete spire round a stick; Aristolochia gigas revolved in about 5 hrs., but took 9 hrs. 15 m. to complete its spire. This, I presume, is due to the continued disturbance of the impelling force by the arrestment of the movement at successive points; and we shall hereafter see that even shaking a plant retards the revolving movement. ”

“ If we hold in our left hand a bundle of parallel strings, we can with our right hand turn these round and round, thus imitating the revolving movement of a twining plant, and the strings do not become twisted. But if we hold at the same time a stick in our left hand, in such a position that the strings become spirally turned round it, they will inevitably become twisted. ”

“ Now if a coloured streak be painted (this was done with a large number of twining plants) along, we will say, the convex line of surface, this coloured streak will after a time (depending on the rate of revolution) be found to lie along one side of the bow, then along the concave side, then on the opposite side, and, lastly, again on the original convex surface. This clearly proves that the internodes, during the revolving movement, become bowed in every direction. The movement is, in fact, a continuous self-bowing of the whole shoot, successively directed to all points of the compass. ”

“ To increase the length of a lever is to increase its power at one end, and the distance through which it moves at the other; hence the faculty of bounding or leaping possessed in such perfection by many quadrupeds.34 If the wing be considered as a lever, a small degree of motion at its root produces an extensive sweep at its tip. ”

“ Gerald read, “should try to develop a long, easy stride. He should not, however, exhaust himself seeking to attain a length of stride which his build naturally prohibits. An unnatural stride results in exhaustion. By careful practice he may add to the length of stride by just that little within his power, and which may mean a great deal in a contest. Remember that in distance running every inch added to the stride means seconds gained at the finish.” ”

“ Sometimes on seizing a branch in her progress, she will throw herself, by one arm only, completely round it, making a revolution with such rapidity as almost to deceive the eye, and continue her progress with undiminished velocity. ”

“ The sun beat oppressively on his head and blistered his shoulders through his net undershirt. The warm water soaked the energy out of limbs and arms. He changed from breast to over-arm stroke, then he shifted to the crawl and trudgen stroke. ”

“ The number of steps which a person can take in a given time in walking depends, first, on the length of the leg, which, governed by the laws of the pendulum, swings from behind forwards; secondly, on the earlier or later interruption which the leg experiences in its arc of oscillation by being placed on the ground. The weight of the swinging leg and the velocity of the trunk serve to give the impulse by which the foot attains a position vertical to the head of the thigh-bone ”

“ When a free shoot has grown far beyond its support, it sinks downwards from its weight, as already explained in the case of the Hop, with the revolving extremity turned upwards. If the support be not lofty, the shoot falls to the ground, and resting there, the extremity rises up. ”

“ In following an old male who had been travelling at full speed I found that its stride averaged twenty-eight feet, but at the same time he kept so close to the ground that midway of the stride, when one foot was carried forward, it scraped the sand. ”

“ On one occasion, choosing for the performance the steepest and narrowest place in the path, right on the edge of a precipice, he managed, first to lose his fore legs in a burrow, and nearly to crush his rider’s leg against a projecting rock, then in struggling out to lose both his hind legs in another burrow, and to finish up by falling over backwards. ”

“ If I would remain with my head above the well-rim—which, I freely admit, I had an unphilosophic desire to do—I must swarm as persistently up the rope. That was an eerie and airy sort of treadmill. To climb, and climb, and always climb, paying out the cord beneath me, that I might remain in one place! ”

“ Back in the shallows once more, they had the most glorious of water-fights, smiting the smooth surface with the heel of their hands, and sending it rattling like buck-shot upon one another's streaming head and shoulders. ”

“ We can, however, see, in accordance with the views previously explained, that a revolving shoot, which, after coming into contact with any support, quickly lost its power of movement, would not again be drawn away from its support by the returning or opposite movement, and therefore remaining in contact with it, might thus ascend a thick support. But whether this slight difference in retaining for some time or in quickly losing the power of movement after coming into contact with a support alone determines how thick an object the stem can ascend I do not know. ”

“ When the shoot follows the sun in its revolving course, it winds round the support from right to left, the support being supposed to stand in front of the beholder; when the shoot revolves in an opposite direction, the line of winding is reversed. As each internode loses from age its power of revolving, it likewise loses its power of spirally twining. If a man swings a rope round his head, and the end hits a stick, it will coil round the stick according to the direction of the swinging movement ”

“ Sometimes they would suddenly form a circle, and, with a simultaneous jerk of their heads, throw their long hair, so that the ends would for a moment all meet together in the centre; at other times, rolling their heads upon their shoulders with such astonishing velocity, that the eye was dazzled as they flew round and round, their hair radiating and diverging like the thrumbings of a mop, when trundled by some strong-limbed housemaid. ”

“ In the ordinary trot, or in that in which the animal’s strides are very long, the body between each of the double pressures which we have just been considering is projected forward with such force that it remains for an instant separated from the ground. ”

“ If one falls on such ground, one instantly begins to slide down the incline with rapidly increasing velocity, and, unless some friendly bush or stone arrests one's progress, the chances are that one is carried over some precipice, and either killed or severely injured. ”

“ Once a farmer's big dog rushed angrily into the road and she swerved until she almost fell, but she regained her balance, and setting her muscles, pedaled as fast as she could. At last she lifted her head. Surely it could not be over a mile more. She had covered two of corduroy and at least three of gravel, and it was only six in all. ”

“ The distance by which the near hind foot passes the near fore foot in rapid walking, trotting, and galloping, increases in a progressive ratio, and is due in a principal measure to the velocity or momentum acquired by the mass of the horse in rapid motion; the body of the animal carrying forward and planting the limbs at greater relative distances in the trot than in the rapid walk, and in the gallop than in the trot. ”

“ Your feet should be "home" in the stirrups, and you will naturally throw them slightly backward as you hold on, toes down, because it both gives you the better grip and keeps your stirrup on your foot. In this particular, Tom, I bid you heed my precept, and not study my example, which is by no means of the best, as I am reduced to jumping with a straight leg, and to fastening my stirrup to my foot, lest I should not find it when I land. ”

“ From the fact that a single stride is said to cover twenty-five feet or more, it will readily be understood that the speed is very great, exceeding that of a galloping horse; but, owing to its habit of running in a curve, it is generally possible to intercept the bird's path at a distance from the point where it started. ”

“ If the bird be diminishing from before, behind, or from the side, the up and down strokes of the pinion distract the attention and complicate the movement to such an extent as to render the observation of little value. In watching rooks proceeding leisurely against a slight breeze, I have over and over again satisfied myself that the wings are flexed during the up stroke, the mere extension and flexion, with very little of a down stroke, in such instances sufficing for propulsion. ”

“ The movement is frequently such that three of the sides of the shoot seem to be growing in due order more rapidly than the remaining side; so that a semi-circle instead of a circle is described, the shoot becoming straight and upright during half of its course. ”

“ Too much slipping will help to create it. But the most important thing that causes cross-firing, nine times out of ten, is because the hind feet are a lot higher on the inside than they are on the outside, which creates a leverage to leave the ground from when at speed, which extra height or length of foot acts as a leverage to control the line of action of the leg after the foot leaves the ground. ”

“ This is easily proved; for when the lower half or two-thirds of a long revolving shoot is tied to a stick, the upper free part continues steadily revolving. Even if the whole shoot, except an inch or two of the extremity, be tied up, this part, as I have seen in the case of the Hop, Ceropegia, Convolvulus, &c., goes on revolving, but much more slowly; for the internodes, until they have grown to some little length, always move slowly. ”

“ For on the faded fronds of that dead palm, she saw, hung her one and only hope.
She wormed her way to the edge of the box-couch, letting herself drop limply to the floor. Then by much writhing and working of her torso she placed herself in position for rolling toward the bamboo table. These movements were painful. But she worked both methodically and patiently, for by this time she had arrived at a definite plan of action. And as she rolled toward the fragile-looking bamboo table she did so with all the vigor at her command. She bore down on it, in fact, with ever accelerating speed. ”

“ It is a mistake to imagine that people are dragged owing to the stirrup being too large, and the foot passing through it; such accidents arise from the stirrup being too small, and the foot clasped by the pressure of the upper part on the toe and the lower part on the sole. ”

“ It is generally admitted that a step is constituted by the series of movements which are produced between the corresponding phases of the action of one foot and that of the other—for example, between the moment at which the right foot commences its pressure on the ground and that at which the left foot commences its own. ”

“ Half a stride means some six or seven feet; to leave the ground that much too soon adds the width of a fair-sized ditch to his task, and if the sum total prove too much for him you cannot be surprised at the result. ”

“ As with a few exceptions tendrils spontaneously revolve, it may be asked,—why have they been endowed with sensitiveness?—why, when they come into contact with a stick, do they not, like twining plants, spirally wind round it? One reason may be that they are in most cases so flexible and thin, that when brought into contact with any object, they would almost certainly yield and be dragged onwards by the revolving movement. ”

“ Meanwhile the climbing and leaping from branch to branch, the measuring with the eye of distances and strength of branches, the power of grasping the right point at the right instant, and all the complicated series of movements combined in this form of locomotion furnished a marvellous set of exercises not only for the muscles but for the higher centres in the cortex of the brain. ”