920 Jiddttilecander.on 
This didprapes is that of | the extremes; and as t 
mber of observations is as likely to be plu 
mean error . ° oF. 
t 167 = 
pies at 228 
ot. 
ne av erage of which, 
amount of error, plus or mi leat 
with 
f Mr. ee are still 5 be a 
