SUMATRA. 
"5 
principles of calculation, by which to determine at any time» the prei- 
bable future produce of the different refidencits. Thele will depend 
upon a knowledge of the medium prockice of a determinate number of 
vines, and the medium number to which this produce is to be applied; 
both of which are to be afcertained only from a comprehenlh e riew of 
the fubje£t, and a nice difcriniination* Nothing general can be deter- 
mined from detached inftances. It is not the produce of one pardcuhr 
plantation, in one particular ftage of bearing, and in one particular fea- 
Ibn ; but the mean produce of all the various clafTes of bearing vines 
coUedivcly, drawn from the experience of feveral years, that can alone be 
depended on in calculations of this nature. So in regard to the medium 
number of vines prefumed to exift at any refidency in a future year, to 
which the medium pmdnce of a certain numberj one thoufand forinftance;- 
is to be applied, the quantity of young vines of the firft, fecond and third 
year, muft not be indifcriminately advanced, in their whole- extent, to 
the next annual ftage, but a judicious allowance, founded on experience 
muft be made, for the accidents to which, in fpire of a refident's utmofir 
care, they will be expofed. Some are loft by negled or death of 
the owner s fome are deftroyed by inundations, others by elephants and 
Tvild buffaloes, and fome by unfavorable feaf >ns; and from thefe feverat 
confiderations, the number of vines will ever be found confiderably 
decreafed, by the time they have arrived at a bearing ftate. Another im- 
portant objedt of confideration, in thefe matters, is the comparative 
itate of a rehdent)- at fxn^ Darticular period, with what may be juftly 
confidered as its medium ftate. There muft exift a determinate propor- 
tion, between any number of bearing vines, and fuch a number of young 
as are neceflary to replace them when they go off and keep up a regular 
fuccclion. This will depend in general upon the length of time before 
they reach a bearing ftate, and during which they afterwards continue in 
it. If this certain proportion happens at any time to- be difturbed, the 
p^^uce mull become irregular. 'I hus>ifat any period, the number of 
bearing vines fliall be found to exceed their juft proportion to the totai 
number, the produce, at fuch period, is to be con^idered as above the 
mean, and a fubfequent dccfcafe may be with certainty predi^ed, and. 
