li)oy he add^d, tar tfe bin^lit afjt^f Common u eai h 
Learning 5 both theFiiKler and Reiater wili think their 
time and pains very both beftowed and recom^ 
penced, 
2he exaS Figure (partofwbdt the Author infendcd^ if 
he had lived ) of two of the Tecth^ is here engraved Fig. 9« 
|7e Part oj a Letm.gmng an Account of a perfon 
who can neither Read nor Write^ yet mil reckon 
Siimms to great examine fs. Communicatee/ b/ 
Mr Locke ' 
Rotterdam, March 23. 170 
YEftprday I had here a young Lad of 17 years old, 
that can neither read nor write, that out of his head 
will reckon any the moft difficult fumms you can give 
him, even to the utmoft fraftions* I gave him an ave- 
rage to make of a Ship run afliore, to fave Ship and Goods 
were worth 13679,14, the charges on the falvage was 
293I516. I askc him how much that \n^2iS per Cent, he 
told me, after a little talking to himfelf, that it v\?as 21 
gild. 9 ft. and a fmall fraftion, and fo it is. I askt him 
what 4945,5, 2848,4, 2244,7, 2194,7, 544,19, 551,18, 
and 52,16 muft pay refpedtively, he told me exaftly to fa 
many Stivers and ^Uk. I askt how he came by that know- 
ledge, he faid by felling Sea Snails (^Alykreuckeny^v^AMu.^' 
cles, for which he received nothing but doits, and fo he 
brought his Father home fo many doits, but could never 
tell how much money they amounted to, till he askt his 
Father how many doits made a gilder, and being 160,, 
then 
