1820.] Royal Academy of Sciences. 59 



for nothing else.' The director of the school ordered him to 

 calculate a particular case of defilement, an operation in which 

 the relief and groundwork of fortifications is to be combined 

 together with the smallest possible charge, but so that the 

 defenders may be sheltered from the shot of the assailants. 

 Monge abandoned the method hitherto followed, and discovered 

 the first general geometrical method that was known for this 



important operation By applying, at different times, his 



mathematical talents to questions of a similar nature, and always 

 generalizing his manner of conceiving and working them, he, at 

 last, formed a scientific work on the subject ; this was his 



Descriptive Geometry For more than 20 years, he found it 



impossible to show to the corps stationed at Mezieres the appli- 

 cation of his geometry to carpentry. He was more successful in 

 its application to masonry ; he studied with great care the 

 methods hitherto employed, and simplifying them he brought 

 them to perfection by his geometry." 



" His scientific works caused him to be appointed Acting 

 Professor of the Mathematics and Natural Philosophy, in the 

 room of NoUet and Bossut ; afterwards he was appointed Hono- 

 rary Professor : he then turned his views towards the study of 

 many phenomena of nature ; he made numerous experiments 

 upon electricity ; he explained the phenomena which arise from 

 capillary attraction ; was the creator of an ingenious system of 

 meteorology ; he examined the composition of water, having 

 made that great discovery without having any knowledge of the 

 experiments which had just before been made by Lavoisier, 

 Laplace, and Cavendish. He did not content himself with 

 explaining to his pupils in the theatre of the school the theories 

 of science and their application : he loved to conduct his disciples 

 wherever the phenomena of nature, or the works of art, could 

 render these applications apparent and interesting. He commu- 

 nicated his own ardour and enthusiasm to his pupils, and changed 

 those observations and researches into desirable pleasures, which 

 would have appeared to be a disagreeable study in the confine- 

 ment of a school, and clothed only in abstract ideas." 



" In order to bring Monge to Paris, he was appointed in 1780 

 assistant to Bossut, Professor of the Hydrodynamic Course, 

 instituted by Turgot. That he might reconcile the duty of the 

 two places which he now held, he lived six months at Mezieres, 

 and six months at Paris. The same year he was admitted into 

 the Academy of Sciences ; and on the death of Bezout in 1783, 

 he was chosen to succeed that celebrated examiner of the naval 

 service. The Marquis de Castries invited Monge several times 

 to write another elementary course of the mathematics for the 

 youths of the naval service, but Monge always refused to comply. 

 Bezout, said he, has left a widow with no other fortune than her 

 late husband's works, and I do not wish to take away the bread 

 from the widow of one who has rendered important services to 



