Vol. XXII. No. 5.] 



POPULAE SCIENCE iSfEWS. 



67 



f 



Fro. 4. 



known to builders, that, when there is required a 

 pillar of a given strength, less material is needed 

 for the tubular form than for the solid cylinder. 



But to return to our flower. We have next to 

 consider how the visits of insects are utilized to 

 secure cross-fertilization. If we examine the 

 anther-tube of a flower that has just opened (Fig 

 4), we shall see that the style has not yet pro- 

 truded, but fills the entire cavity, except such space 

 as is occupied by a quantity of pollen which the 

 anthers have shed. So much of the style as is 

 within the tube is thickly be- 

 set with hairs that point up- 

 wards; and when the lower 

 portion elongates, this hairy 

 part brushes the pollen out of 

 the tube, and protrudes, cov- 

 ered with the yellow dust (Fig. 

 5). At this stage, an insect 

 coming for nectar must rub 

 against the style, and so be- 

 come more or less covered with 

 pollen. None of it, however, 

 can get upon the stigmas, for 

 they are not yet exposed. 

 After a short time has elapsed, 

 during which much of the pol- 

 len has probably been rubbed off, the style is seen 

 to split at the top; and as the halves separate and 

 roll back (Fig. 3), their inner faces (the stigmas) 

 are exposed. If, now, the flower be visited by an 

 insect which has previously been to a younger 

 flower, the pollen he brings will be deposited upon 

 the stigmas as he rubs against them, and cross- 

 fertilization will be effected. 



Let us suppose, howevei-, that no insect visits the 

 blossom, — and this must often happen to such as 

 appear very early in the sprine; or late in the fall, 

 when hardly any insects are around. In such 

 cases we find that seeds are produced, and ttiere- 

 fore we must infer that fertilization has in some 

 way or other been secured. An examination of a 

 flower still older than any we have 

 I considered (Fig. 6) will show us what 

 takes place. Here it will be seen, 

 that, after the stigmas have diverged, 

 they continue to roll back,, until a coil 

 of one or more turns has been made; 

 and as a result of this the stigmatic 

 surface comes in contact with the 

 hairs on the style, and touches the 

 pollen grains entangled by them. 

 Still, the close-fertilization thus ac- 

 complished is only a last resort, and 

 it can only occur in the event of in- 

 sects' visits having failed; for when 

 pollen from another flower has once 

 fallen on the stigma, no pollen com- 

 ing afterwards can have the least effect. Thus, 

 we have another instance of the dandelion's ability 

 to make the best of its surroundings. 



It even adapts itself to the weather ; for when 

 the sun shines, the scales of the involucre bend 

 back, and the blossom is expanded to its fullest 

 extent; but in dull weather, or at night, the scales 

 bend inwards, and the blossom is tightly closed. 

 The advantages of this remarkable movement, with 

 its implied sensitiveness, is obvious when we con- 

 sider that insects are abroad only in sunshine, 

 while at other times there is danger of dew or rain 

 getting into the nectar, and so spoiling it for the 

 insects. 



After fertilization hius been accomplished 

 throughout the blossom, the involucre closes, and 

 remains closed during the ripening of the fruit. 

 The changes which now take place are as follows: 

 In each flower the corolla, stamens, and style, be- 

 ing of no further use, wither, and sever their con- 



/ 



nection with the ovary ; the ovule develops into a 

 seed containing a tiny plantlet well provided wijh 

 food for its use during germination; the ovary 

 grows to keep pace with the seed, its tissues be- 

 come hardened, and a number of spine-like projec- 

 tions develop near the upper part; and finally the 

 short neck which bears the calyx bristles elongates, 

 pushing upwards the withered parts of the flower. 

 At this stage the involucral scales bend back 

 through an arc of about 180°, . the cushion-like 

 receptacle becomes almost spherically convex, the 

 fruits radiate in all directions, the bristles spread, 

 and a beautiful cluster of little parachutes is pre- 

 sented to the wind. 



Even a glance at one of these fruits (Fig. 7) is 

 sufficient to discover a wonderful fitness for trans- 

 portation by wind, and more careful study shows 

 that this fitness pervades every detail. For exam- 

 ple, on examining the bristles microscopically 

 (Fig. 8), it is shown that they are not simple 

 threads, but each is hollow and has numerous pro- 

 jections extending on either side, all of which 

 serves to increase the buoyancy in a very effective 

 way. 



The experience of aeronauts has shown that a 

 highly important part in the equipment of a bal- 

 loon, after the attainment of buoyancy, is the pro- 

 vision of some means of arresting the balloon's 



Fig. 7. Fia. 8. 



progress when (he destination has been reached 

 One of the most successful means which they 

 employ is the grappling hook; and as we find the 

 base of our diminutive parachute provided with a 

 number of upwardly directed spines, it seems fair 

 to conclude that these serve to arrest the fruit upon 

 favorable soil. If it comes to rest upon a smooth 

 surface, — which, of course, would be barren, — the 

 next breeze would ea.sily blow it away; but if it 

 chance to fall on soil or among other plants, the 

 effect of the spines would be to retain it against 

 the power of even a strong wind. Thus, we may 

 leave it safely landed upon good soil, ready to be- 

 gin, under favorable conditions, the cycle of its 

 wonderful life. 



[Original in Popular Science NewtJ] 



THE FRENCH ACADEMY OF SCIE^fCES. 



M. E. Maindron, who has been during many 

 years intrusted with important functions in the 

 management of the Academy of Sciences, has re- 

 cently given a good account of the history of this 

 important scientific body; and we have deemed it 

 of some interest to your readers to give an abstract 

 of his book.' 



Before 1666 the Academy was an unoflicial soci- 

 ety of scientific men, without any determined pur- 

 pose, which assembled together, at fixed days, in 

 the rooms of some of the members. It had no 

 periodical papei\ Among the members of this 

 society were Descartes, the /'ere Mersenne, Pascal 



' L' Academie des Sciencet, vol. iii. 8vo, 339 pagea, with 61 

 pictures, autographs, portraits, etc. Paris ; Alcan, 1888. 



(Blaise and his father fitienne), Gassendi, etc. 

 At the end of 1666 Louis XIV. and Colbert de- 

 cided to allow this society to meet in the rooms of 

 the Royal Library, and to raise some funds, which 

 were used for pensions and experiments. No docu- 

 ment exists showing how the members were to be 

 elected nor how the ,\cademy was to be managed. 

 In 1666, among the members we find the names 

 of Huyghens, Mariotte, Pecquet, Perrault, etc. 

 For the first time a regular account is given of 

 each assembly. The members met twice a week, 

 Wednesday and Saturday, and were of two classes, 



— physicists and mathematicians ; for the first time 

 the society was called Academie des Sciences. 

 Such were the beginnings of this scientific corpo- 

 ration, in commemoration of which a now well- 

 known medal was engraved. Illustrious visitors 

 attended occasionally its meetings. The visits of 

 James 11., king of England, and of Louis XIV., 

 are recorded in the annals of 1690 and 1681. But 

 at this period the organization of the Academy was 

 quite of a provisional character; nothing had been 

 decided concerning its management, the elections, 

 and the purpose of the Academy. It is in 1699 

 only, that, on the order of the king, the.?e ques- 

 tions were decided. In the charter of January, 

 1699, it is decided that the Academy shall con- 

 sist of ten honorary members (physicists or math- 

 ematicians); twenty pensionnaires (three geometri- 

 cians, three astronomers, three chemists, three 

 anatomists, three botanists, three concerned with 

 mechanical pursuits, one secretary, and one treas- 

 urer); twenty associates, fourteen national (two for 

 each of the foregoing sciences), the eight others 

 being chosen, if desirable, among distinguished 

 foreigners; twenty e/eMs, or pupils, each of which 

 was a sort of assistant to an associate, and engaged 

 in the same pursuits. The elections were to be 

 made in the following manner: the Academy to 

 propose two or three names for each place, and the 

 king to choose one. The members were, at the 

 beginning of each year, to inform the Academy of 

 the questions they intended to study. As a body, 

 the Academy was to repeat all experiments com- 

 municated to her by the members or by strangers, 

 and to give her opinion on the matter. At this time 

 the more illustrious members of the Academy were 

 Malebranche, Cassini, ^Icry, Tournefort, Foute- 

 nelle, Leibnitz, Ldmery. The first meeting of the 

 now regularly constituted Academy was held on 

 April 29, 1699, in the Louvre palace, in new rooms 

 which the king decided to set apart for the new 

 society, with a library already well brought up, 

 with a fine collection of scientific instruments and 

 natural-history specimens. The Academy set to 

 work with much zeal, and nothing particular is to 

 be recorded till 1785, when a new rule was en- 

 forced. The Academy was divided in eight classes, 



— geometry, astronomy, mechanics, physics anat- 

 omy, chemistry and metallurgy, botany and agri- 

 culture, natural history and mineralogy. Each 

 class was to consist of six members (three pension- 

 naires and three associates), nothing being changed 

 concerning the secretary and treasurer, the twelve 

 honorary, the twelve associes libres, and the eight 

 foreign associates. At this time the more illustri- 

 ous members were Lalande, Laplace, Cassini, 

 Daubenton, Lavoisier, Berthollet, Vicq-d'Azyr, 

 Fourcroy, Adanson, De Jussien, Lamarck, Haiiy, 

 Bernouilli, Franklin, Euler, Priestley, Hunter; the 

 five last named, in the class of foreign associates. 

 In 1793 (8th of August) the revolutionary gov- 

 ernment decided to suppress the Academy of Sci- 

 ences: — 



" Art. I. — All academies and literary socie- 

 ties patented and paid by the nation' are suppressed. " 

 The 10th of the same month, Lavoisier wrote to 

 Lakanal, president of the Committee on Public In- 



