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I have not attained sufficient know. food, and one while lying at rest ; ledge of the aninial to speak with there are a little magnified, to show the finallest certainty.
the parts more distinctly. " I have endeavoured to describe “'I shall not say any thing of the external appearances as I saw the internal parts, or their uses, as them; and have annexed two the animal is in your possession, drawings of the animal in its two who are so much better able to exdifferent itates, one in search of plain its internal economy.
An ACCOUNT of the SENSITIVE. QUALITY of the TREE AVERRHOA CARAMBOLA. By ROFERT BRUCE, M. D.
( Frony the faine Publication. ] "T"
IIE Averrhoa Carambola another, whilst the opposite cona
of Linnæus, a tree called tinue as they were; or you may in Bengal the Camruc, or Cam- mitke them move alternately, or, runga, is potlefied of a power fome. in thort, in any order you please, what fimilar to those species of by touching in a proper manner Mimola which are termed tenli- the leaf you wish to put in motion. tive plants : its leaves, on being But if the impreffion, although touched, move very perceptibly. made on a single leaf, be strong,
• In the Mimofa the moving fa. all the leaves on that pinna, and culty extends to the branches; sometimes on the neighbouring but, from the hardness of the wood, ones, will be affected by it. this cannot be expected in the Cam- " What at first teemed surprising runga. The leaves are alternately was, that, notwithstand ng this
appinnated, with an odd one; and in parent fentibility of the leaf, I their most common potition in the could with a pair of sharp fciffars day-time are horizontal, or on the make large incifions in it, without famne plane with the branch froin occasioning the smallett motion ; which they come out. On being nay, even cut it almost entirely off, touched, they move themselves and the rem..ining part still contie downward, frequently in fo great nue uvmoved; and that then, by a degree that the two oppolite al. touching the wounded leaf with moit touch one another by their the finger or point of the scissars, under fides, and the young ones motion would take place as if no fometimes either come into con- injury had been offered. But, on tact or even pass each other. further examination, I found, that,
" The whole of the leaves of although the leaf was the oftenone pinna more by striking the tible part which moved, it was in branch with the nail of the finger, fact entirely pallive, and that the or other hard fubitance; or each petiolus was the seat both of sense leaf can be moved lingly, by mak. and action; for, although the leaf ing an impreifion that thall not ex. might be cut in pieces, or squeezed tend beyond that leaf. In this way with great force, provided its die the leaves of one side of the pinna rection was not changed, without may be made to nove, one after any motion being occafioned, yet, 1785.
the impreslion on the leaf was made veral others which were nearer the in such a way as to affect the pe- place where the pin was put in. tiolus, the motion took place. “ On making a compreifion with When, therefore, I wanted to con- a pair of pincers on the universal fine the motion to a single leaf, I petiolus, between any two pair of either touched it so as only to af- leaves, those above the compressed fect its own petiolus, or, without part, or nearer the extremity of meddling with the leaf, touched the petiolus, move fooner than the petiolus with any small-pointed thote under it, or nearer the oribody, as a pin or knife.
gin; and frequently the motion • By compressing the universal will extend upwards to the extreme petiolus near the place where a leaf, whilst below it perhaps does partial one comes out, the leaf not go farther than the nearest pair. moves in a few seconds, in the same " If the leaves happen to be manner as if you had touched the blown by the wind againit one anpartial petiolus.
other, or against the branches, they • Whether the impression be are frequently put in motion; but made by puncture, percussion, or when a branch is moved gently, compression, the motion does not either by the hand or the wind, instantly follow : generally several without striking against any thing, seconds' intervene, and then it is no motion of the leaves takes place. not by a jirk, but regular and gra- " When left to themselves in dual. Afterwards, when the leaves the day-time, fhaded from the fun, return to their former situation, wind, rain, or any disturbing cause, which is cominonly in a quarter of the appearance of the leaves is dit. an hour or less, it is in to flow a ferent from that of other pinnated manner as to be almost impercep. plants. In the last a great unitible.
forinity lublilts in the respective « On sticking a pin into the uni- potition of the leaves on the pinna; versal petiolus at its origin, the but here some will be seen on the leaf next it, which is always on horizontal plane, fome raised above the outer fide, moves first; then it, and others fallen under it; and the first leaf on the oppolite tide, in an hour or so, without any ornext the second deat on the outer, der or regularity, which I could and so on. But this regular pro- observe, all these will have chang. gressiun feldom continues through- ed their respective positions. I have out ; for the leaves on the outer seen a leat, which was high up, fide of the pinna seem to be affect- fall down ; this it did as quickly ed both more quickly, and with as if a strong impression had been more energy, than those of the made on it, but there was no cause inner, so that the fourth leaf on to be perceived. the outer lide frequently moves as “ Cutting the bark of the branch soon as the third on the inner; and down to the wood, and even sepasometimes a leaf, especially on the rating it about the space of half an inner side, does not move at all, inch all round, so as to itop all comwhilst thoic above and below it are munication by the vessels of the affecied in their proper time. Some bark, does not for the first day aftimes the leaves at the extremity of fećt the leaves, either in their po. the etiolus move fooner than fe. fition or their aptitude for motion.
“ In a branch, which I cut from the electrical shock, even al. through in such a manner as to though a very gentle one ; but the leave it suspended only by a little state of the atmosphere was so un. of the bark no thicker than a favourable for experiments of this thread, the leaves next day did not kind, that I could not pursue them rise fo high as the others; but they fo far as I wished, were green and fresli, and, on being 66 There are two other plants touched, moved, but in a much less mentioned as fpecies of this genus degree than forinerly.
by Linneus. The first, the Aver“ After sun-let the leaves go to rhoa Bilimbi, I have not had an fleep, first moving down so as to opportunity of seeing. The other, touch one another by their under or Averrhoa Acida, does not leem fides: they therefore perforın ra- to belong to the fame class; nor ther more extensive motion at night do its leaves possess any of the of themselves than they can be moving properties of the Carammade to do in the day-time by ex- bola. Linnæus's generic descripternal impressions. With a convex tion of the Averrhoa, as of many lens I have collected the rays of other plants in this country which the sun on a leaf, so as to burn a he had not an opportunity of seeing hole in it, without occafioning any fresa, is not altogether accurate. motion. But when the experiment The petals are connected by the was tried on the petiolus, the mo- lower part of the lamina, and in tion is as quick as if from trong this way they fall off whild the percussion, although the rays were ungues are quite distinct. The sta. pot fo much concentrated as to mina are in five pairs, placed iq çause pain when applied in the the angles of the gerinen. Of cach fame degree on the back of the pair only one stamen is fertile, hand; nor had the texture of the furnished with an anthera. The petiolus been any ways changed filaments are curved, adapted to the by this ; for next day it could not Mape of the germen. They may be distinguished, either by its ap- be preffed down gently, so as to pearance or proving power, from remain ; and then, when moved a those on which uo experiment had little upwards, rise with a spring. been made.
The fertile are twice the length of 56 The leaves move very fast those deftitute of antheræ."
A. ACCOUNT of some EXPERIMENTS on the LOSS of WEIGHT
in BODIES, on being melted or heated. By GEORGE FORDYCE, M. D. E. R. S.
[ From the fame Publication. ] Lthough I have made many contradiction in them. I fall cons
experiments on the subject tent myself with relating the folof the loss of weight in hodies on lowing one, which appears to me being melted or heated, I do not conclufixe in determining the loss think it worth while to lay them all of weight in ice when thiwed into before the Society, as there has water, and subject to the least fale not appeared any circumstance of lacy of any I have hitherto made,
in shewing the loss of weight In ice for about a minute, I found it beon being heated.
gan to lose weight, on which I “ The beam I inade use of was immediately took it out, and placed so adjusted as that, with a weight it at a distance from the beam. I between four and five ounces in also immediately plunged a ther. each scale, roso part of a grain mometer in the freezing mixture, made a difference of one division and found the temperature 1o de on the index. It was placed in a grecs ; and on putting the ball of rooin, the heat of which was 37 the thermometer in the hollow at degrees of Fahrenheit's thermo- the bottoin of the glass vessel, it meter, between one and two in the thewed 1 2 degrees. I left the whole afternoon, and left till the whole for half an hour, and found the apparatus and the brass weights ac. thermometer, applied to the holquired the same temperature. low of the glass, at 32o. Every
“ A glass globe, of three inches thing now being at the same temdiameter nearly, with an indenta. perature, I weighed the glass contion at the bottom, and a tube at taining the ice, after wiping it carethe top, weighing about 451 grains, fully, and found it had lost had about 1700 grains of New• five divisions; so that it weighed river water poured into it, and was tr, all but one division, more than hermetically sealed, so that the when the water was fluid. whole, when perfectly clean, weigh
" I now melted the ice, except. ed 2150 # of a grain exactly ; ing a very finall quantity, and leit the heat being brought to 32 de- the glass vessel exposed to the air grees, by placing it in a cooling in the temperature of 32 degrees mixture of salt and ice till it just for a quarter of an hour: the little began to freeze, and shaking the bit of ice continued nearly the whole together.
same. I now weighed it, after “ After it was weighed it was carefully, wiping the glass, and again put into the freezing mix- found it heavier than the water was ture, and let stand for about 20 at first, one divilion of the beam. minutes ; it was then taken out of Lastly, I took out the weights, the mixture : part of the water was and found the beam exactly baa found to be frozen; and it was lanced as before the experiment. carefully wiped, first with a dry " The acquisition of weight linen cloth, and afterwards with found on water's being converted dry washed leather; and on putting into ice, may arise from an increase it into the scale it was found to have of the attraction of gravitation of gained about the a part of a grain. the matter of the water; or from This was repeated five times : at some substance imbibed through cach time more of the water was the glass, which is necessary to frozen, and more weight gained. render the water solid. In the mean time the heat of the " Which of these positions is room and apparatus had sunk to true may be determined by formthe freezing point.
ing a pendulum of water, and an“ When the whole was frozen, other of ice, of the same length, it was carefully wiped and weighed, and in every other respect fimilar, and found to have gained 1% of a and making them fwing equal arcs. grain and four divisions of the in. If they mark equal times, then dex. Upon standing in the scale certainly there is fome matter added
to the water. If the pendulum of cause of the gain of weight in the ice is quicker in its vibrations, conversion of water into ice in a than the attraction of gravitation is glass veffel hermetically sealed. increased. For there is no pofition “ 1. Thall only observe, that heat more certain, than that a single certainly diminithes the attractions particle of inanimate matter is per- of coheton, chemistry, magnetism, fectly incapable of putting itself in and electricity; and if it should motion, or bringing itself to rest; also turn out, that it diminishes the and therefore that a certain force attraction of gravitation, I should applied to any mass of inatter, fo not helitate to confider heat as the as to give it a certain velocity, will quality of diminution of attraction, give half the quantity of matter which would in that case account double the velocity, and twice the for all its effects. quantity, half the velocity; and “ We come, in the next place, generally a velocity exactly in the to take notice of the second part of inverse proportion to the quantity the experiment, viz. that the ice of matter. Now, if there be the gained an eighth part of a grain on same quantity of matter in water being cooled to 12 degrees of Fahe as there is in ice, and if the force renheit's thermometer. In this of gravity in water be zgico part case, a variation may arise from the less than in ice, and the pendulum contraction of the glass vessel, and of ice fwing feconds, the pendulum consequent increase of specific gra. of water will lose Too of a fe- vity in proportion to the air. But cond in each vibration, or one fe- it is unnecessary to observe, that cond in 28000, which is almost this would be fo very small a quan. three seconds a day, a quantity tity as not to be observable upon a easily measured.
beam adjusted only to the degree of “ I shall just take notice of an fenfibility with which this experiopinion which has been adopted by ment was tried. In the second fome, that there is matter absolute place, the air cooled by the icc ly light, or which repels instead of above the scale becoming heavier attracting other matter. I confess than the furrounding atmosphere, this appears abfurd to me; but the would press upon the scale downfollowing experiment would prove ward with the whole force of the or disprove it. Suppofing, for in- difference. If a little more than 1tance, that heat was a body, and half a pint of air was cooled over absolutely light, and that ice gain the scale to the heat of the ice and ed weight by losing heat ; then a glass containing it, that is, 20 de. pendulum of ice would fiving grees below the freezing point, the through the fame are in asso less difference, according to general time than a fimilar pendulum of Roy's table, would have been the water; for the same power would eighth part of a grain, which was not only act upon a lets quantity of the weight acquired; but the air matter, but a counter-acting force within half an inch of the glass would also be taken away.
vefsel being only one degree below “ Till the experiment of the the freezing point, I cannot conpendulum can be made, or fomeceive, that even an eighth part of a other equally certain be suggested pint of air could be cooled over the and made, it would be wasting time scale to 20. degrees below the freezto enter into conjecture about the ing point; nor that the whole dif.