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them, have created doubts whether wooden pon-toons are not preferable.

The Austrians and French use wooden pon-toons, or bateaux, shaped, in some degree, likethe ordinary flat boats of rivers. These, be-longing more properly to the class of militarybridges considered under the head of Bridges ofBoats, will be treated of in Section 3. TheRussian pontoon, made of wood, covered withsail cloth well tarred, or made impervious towater by a solution of gum-elastic, will likewisebe treated of in that section.

M.Dedon* prefers wooden pontoons to copper,which he wishes to see entirely suppressed. Hesays, that a sufficient wooden pontoon may bemade at one-third the expense, and lighter thanone of copper,—may be transported on countrywaggons, and be used either as a bateau ded^barquement, or a pontoon. Some of ourscientific officers, also, prefer the wooden pon-toon ; but military opinion is much divided uponthis subject: the question indeed is relative;the tin pontoon being preferable, when there ismuch land carriage in a hot sun, and the bateaubetter adapted to navigation, and indispensablein wide turbulent rivers.

* Relation du Passage de la Limat, du Rhin, See. page 64,by General Dedon, of the artillery.