MEMOIR OF C. F. BEAUTEMPS-BEAUPRE. 133 



point of the coast souuded, the suitable number of feet, iu order to transfer to 

 the plan only the depths of water lound at each point at the precise instant of 

 lowest depression. The tables of high and low tide, at many principal points 

 on the coasts of France, are extracts frem the large body of observations which 

 served for the reduction of the soundings." [Exjwse dcs Traraux, &c., p. 10.) 

 As M. Beantemps-Bcaupre has more than once remarked, the soundings in 

 many parts of the sea are far from being necessarily unchangeable. It is readily 

 conceived that they must vary as well from the effect of deposits produced at 

 some points as of erosions which take place at others. He had said, as early 

 as 1804, in his nautical description of the coast of the Noi'th sea: " We forewarn 

 navigators that our work must not be regarded as everywhere authoritative, ex- 

 cept for a limited time, on account of the changes which are in progress in the 

 shoals upon these shores." To the same effect he observes with reference to 

 the western and southern coasts of France : " Ail banks of sand and ooze un- 

 dergo changes of position and of depth of which navigators should ever be dis- 

 trustful, since ihe best charts can only give, as regards dangers of this kind, 

 insufficient information when some time has intervened since their construction. 

 And this applies especially to such banks when they obstruct the mouths of 

 rivers. Hence the necessity of sounding annually the principal channels, and, 

 indeed, of frequently renewing the charts of the entrances of rivers." It may 

 be added that the comparison of the successive charts of the same region will 

 some day furnish valuable data respecting the accumulation of sub-marine 

 alluviums. 



It was to the class of researches just spoken of that our colleague dedicated 

 his last hydrographic labor. He had not taken final leave of the sea in closing, 

 in 1839, his survey of the northern coast of France. In 1841, at the age of 

 seventy-five, he cheerfully complied with the invitation of Admiral Baudin to 

 join him in an investigation of the changes produced in the system of bars at 

 the mouth of the Seine within the seven preceding years. It was then that for 

 the first time he had at his disposal a vessel moved by steam, and the superior 

 facilities thus furnished for hydrographic enterprises drew from him the remark, 

 " That he would gladly recommence his career if it were only for the pleasure 

 of pi'osecuting hydrography with such advantages." 



Though he cheerfully acknowledged that the marine had done iu his behalf 

 all that was practicable, yet he had never, during his operations on the coasts 

 of France, possessed other resources for transportation than those supplied by 

 the sail and oar. He had generally at his command a company of eight or ten 

 hydrographical engineers and ofiicers of marine, and from this school of prac- 

 tical hydrography have proceeded many of each class who have since been in- 

 trusted with the most important labors in remote as well as neighboring seas. 

 Among them have appeared at different times our present colleagues, M. Daussy, 

 Admiral du Petit Thenars, and M. Dortet de Tessau; MM. Givry and Gressier, 

 to whom was intrusted, under our distinguished and regretted colleague, Admi- 

 ral Roussin, the hydrography of the coasts of Brazil ; MM. Monnier and Le 

 Bourguignon Duperre, who have furnished us a magnificent chart of our colony 

 of Martinique, and have commenced the hydrographic survey of our Mediter- 

 ranean coasts, and those of Italy ; MM. Begat, Keller, Chazallon, Lisusson, 

 DL-lamarche, de la Roche-Poncie, now actively prosecuting the grand hydro- 

 graphic enterprises of the depot of marine; MM. Darondeau and Vincendon 

 Dumoulin, who have so honorably associated their names with our great voy- 

 ages of circumnavigation and other important labors ; MM. Le Saulnier de 

 Vauhello, Lapierre, Jehenne, De Villeneuve, who, as officers of our marine, 

 have in different quarters of the Avorld rendered signal services to hydrography. 

 Familiar with all the hazards of the sea, M. Beautemps-Beaupre exercised a 

 consummate prudence in the employment of his assistants, and Avas justified in 

 saying to the Academy, when he presented it with the sixth and last volume of 



