REPORT OF CAPT. GEORGE P.. M'CLELLAN. 27 



Otlier materials packed on each wagon vary from Hi to 378 ponnds. 

 Total load of each wagon from 2,340 to 2,574 pounds. 

 Weight of empty wagon, 1,206 pounds. 



The weights and dimensions given ahove are derived from the Russian Aide Memoire of the 

 Engineers, pp. 143 to 145. 



»'■ 



LEATHER PONTONS OF THE MOUNTED ENGINEER TROOPS. 



These are made of varnished leather, stretched over a wooden frame. The boats, or pontons, 

 are 20' long ; greatest width, 5' 7" ; depth, 3' ; weight, 972 pounds ; floatation, when sunk to 

 the depth of 2' 8", 5,760 pounds. 



For each boat there are 8 balks, each 18' long and 4" square, and weighing 72 pounds. 



For each bay there are 12 chesses, each 12' long, 18^" wide, 2" thick, and weighing 101 pounds. 



Each ponton is carried on a wagon, together with 8 balks and some other materials. 



On other wagons are carried the chesses for two bays and the remainder of the material. 



The weights of these wagons and their loads are as follows : 



Boat wason, empty 2,178 pounds. 



The boat 972 " 



8 balks 576 " 



Other materials 540 " 



Total 4,266 " 



Chess wagon, empty 2,196 pounds. 



24 chesses 2,424 " 



Other materials 270 " 



Total 4,890 " 



♦ : 



Each wagon is drawn by 6 horses. 



Each leather boat will transport 25 men, with their arms and accoutrements. 



A raft formed of two boats will transjiort one gun, or 6 horses. 



The foregoing account of this bridge is also derived from the Russian Aide Memoire, (edition 

 of 1848,) pp. 153 and 154. 



I had no opportunity of examining a train of this kind. 



Raft bridges are much employed and admirably handled by the Russians. There is a very 

 fine one, with a draw, over the Vistula, at Modlin. 



FIELD WORKS. 



The normal dimensions of the different parts are as follows : 



Ditch, not less than 10^' wide at top; from 6' to 9' deep; base of scarp and counterscarp from 

 ^ to f of the depth. 



Parapet, from 7' to 8' high ; thickness against infantry, 4' ; against artillery from 9' to 14' ; 

 interior slope, \ ; exterior slope, § or f , according to the soil. 



Banquette, 3' to 4^' wide, 4' 4" below the interior crest. 



Berm, 1^' to 3' wide. 



Embrasures, 1' 9" wide at the throat ; exterior opening depends upon ^he thickness of the 

 parapet and the desired field of fire ; sole, 3' to 3' 3" above the platform. 



