MEMOIR OF AUGUSTE BRAVAIS. - 149 



viserial and rectiserial leaves.) This memoir had nothing- in common 

 with the ordinary hibors of botany relating to the description of species, 

 or to botanical geography. As little was it a memoir on vegetable phy- 

 siology in the usnal acceptation of the word. It was a work of a wholly 

 special and original character on the relations of symmetry, presented 

 by the insertions, at different points of the stem, of the leaves and or- 

 gans which spring from it. This subject, although MM. Bravais had no 

 knowledge of the tact, had shortly before been the subject of a memoir 

 published by two distinguished botanists, ^MM. Schimper and Alexander 

 Braun, who had pointed out its importance, and had arrived at some 

 very curious results. 31. Adolph Bronguiart, however, in the report 

 which he made to the Academy in 1837, pronounced that MM. Louis 

 and Auguste Bravais had brought more precision to the study of the 

 numerous facts which they had collected than had been before exem- 

 plified. The subject, moreover, could not be comi)let»^ly elucidated 

 without a profound knowledge of the helix and of the different spirals 

 in which the insertions of the leaves are aligned with so remarkable a 

 regularity, and withcmt a singular dexterity in the management of con- 

 tinuous fractions, recurrent series, and other mathematical combinations 

 of a delicate nature. M. Auguste Bravais had employed them, with the 

 elegant simplicity which is always the stamp of an accomplished mathe- 

 matician, for exiiressing the relations of position of the leaves with one 

 another, and for arriving in a clear and precise manner at consequences 

 Avhich could not otherwise be obtained except by long and tedious ten- 

 tatives. These deductions have brought to light, in a degree but little 

 suspected by many, a regularity of arrangement in the organs of vege- 

 tables, which, without being precisely analogous to the laws of crystal- 

 lography, is equally as precise and admirable. 



The brothers still further drew up in common different memoirs on 

 botany, and it was not at Paris only that their labors obtained a de- 

 served success. They equally attracted the attention of botanists in 

 other parts of Europe, and M. De CandoUe dedicated to the two authors, 

 under the name of Bravaisia, a new species of the family of the Bignon- 

 iacene. The objects of natin-al history which M. Auguste Bravais sent 

 from Algeria were also highly api^reciated. In 1835 he found on the 

 Island of Eachgoun a serpent which was new to him, the Amphislxjena 

 cincreaj and which he transmitted to M. De Blainville, who testified his 

 surprise at the occurrence of such an animal in that country. Other 

 remittances of seeds and living plants, collected in the province of Oran, 

 earned for him letters of thanks from the administration of the Museum 

 of Paris, and warm encouragements to complete the herbal of Desfon- 

 taines, and to continue his researches in botany during- the voyages it 

 was hoped he would undertake to other regions. 



The ardor of the young officer was so much increased by this success 

 as sometimes to nmke him forget that he was no longer in the peace- 

 able mountains of the Ardecho or of Daitphiny; it drew upon him, on 

 several occasions, the kindly reproaches of his superiors for rashness. 

 But these reproaches were changed into felicitations when, August 12, 

 183G, at the head of thirty-seven marines, he extricated the command- 

 ant and surgeon of the Loiret, surrounded, duriiig a hunting excursion, 

 by the troops of the Emir. 



Unluckily, he did not arrive in time to rescue another officer, whom 

 the Arabs had already carried oft'. But from the point where he then 

 stood M. De France had witnessed the combat, which he describes in his 

 interesting- account of the prisoners of Abd-el-Kader. " I will not con- 

 clude," he says, " without speaking- of the bravery, the coolness, and 



