624 . Mr. mann’s 'freatife 
59. Mr. needham, Director of the Imperial Academy 
of Sciences at Bruxelles, being of opinion that Dr. 
franklin’s experiments were made upon too fmall a 
fcale to draw any very exadt inferences from them, de- 
iired me, at the beginning of the year 177 5, to make a 
new fet of experiments upon a much larger fcale and 
with all poflible exadinefs; I did accordingly, and 111 all 
here give a fliort defcription of them. 
I got made, by the fhip carpenters of Nieuport upon 
the Coaft of Flanders, an exadl model of a bilander, an- 
fwerable in all its proportions to thofe ufed in the Low 
Countries. Its length was thirty-nine Englifh inches, its 
breadth nine inches and a half, and its depth nine inches. 
Its form both within and without exactly reprefented 
that of a bilander. At each end of it was fattened 
perpendicularly a round and polifhed rod, ten inches and 
and a half in height above the ttdes of the boat. 
I got made likewife a wooden canal, twenty feet in 
length, thirty-feven inches in breadth, and fixteen inches 
in depth ; a fedlion of which is reprefented in the fol- 
lowing figure : 
This 
