ACADEMY OF SCIENCES. 163 



be able to compensate the errors of division by successive 

 readings off, and to render the observer independent of 

 the inaccuracies which the artist might have committed 



dJ 



in dividing the circles. Unfortunately natural crystals, 

 on which it is possible to use with any advantage the 

 method of repetition, are by no means common. But 

 the method preserves all its theoretical value when it is 

 the object, in optical researches, to measure the angles of 

 prisms formed by truly worked and perfectly polished 

 planes. At the same time it is but just to observe that 

 the idea of employing the reflexion of light for the meas- 

 urement of angles, is due to the celebrated physicist 

 Lambert. 



MALUS A CANDIDATE FOR THE ACADEMY OF SCIENCES. 

 SITUATIONS WHICH HE FILLED. HIS DEATH. 



The more than ordinary labours of Malus, of which 

 I have just given a rapid analysis, obtained for him the 

 most sincere testimonials of esteem and admiration from 

 men of science of all countries. He was named a mem- 

 ber of the Society of Arcueil, which was composed of a 

 small number of men of science assembling under the 

 auspices of Laplace and Berthollet.* 



A place in the Section of Physics of the Institute hav- 

 ing become vacant in 1810 by the death of Montgolfier, 

 Malus was naturally one of the candidates who presented 

 themselves to fill up the place of the illustrious physicist. 



graduation, be different. As any number of repetitions may be taken, 

 we may have a mean result accurate to any extent desired. Trans- 

 lator. 



* The members of the Society oT Arcueil were Laplace, C. L. Ber- 

 thollet, Biot, Gay-Lussac, Humboldt, The"nard, De Candolle, Collet- 

 Descoutils, A. B. Berthollet, Malus, Arago, Berard, Chaptal, Dulong, 

 Poisson. 



