preface; 
9 
VI 
Win — m i m ——— i mi i n w — —— u m mmmmmmmmm mmmmm mmm t mmmmmmammmm i — a m mmm m mmammmmmm i —— Ji'ft 
' V 
ture ; for want of fuch communications, 
many ufeful acquifitions and difcoveries 
. I 
have been loft to fociety, either by fink- 
* 
ing into oblivion, with the parties in 
whom they originated, or by being im¬ 
properly circumfcribed within too nar¬ 
row limits, have fallen {hort of thofe 
extenfive improvements which they were 
capable of producing. 
It is impoflible to lay down any rules 
on the prefent fubjefl that will always 
t 
fucceed when reduced to pra£lice ; they 
will, on the contrary, be liable to fail 
under peculiar circumftances, fuch as the 
irregularities of. weather, difference of 
feafons, the long duration and extremes 
of heat and cold, and other unavoidable 
cafualties, which are bevond the reach of 
> 0 * • ' ' ‘ ' v 
- - human 
