30 I 
Agricultural Notes on Hertfordshire. 
which only registers that portion of the rainfall which percolates 
3 feet of soil. Its construction is described in ' Ree's Cyclo- 
paedia' under the head Evaporation. It, is calculated that the 
amount so collected represents the quantity which sinks through 
the surface soil to the springs, which supply the rivers and give 
power to the mills. 
The average rainfall registered for 29 years is 22'5, percola- 
tion 7*5 inches. The Table shows 25*8 of rainfall and 4'9 per- 
colation for the last 10 years. It will be seen that the amount of 
rainfall increases with the longitude westward. 
Bl.BKIIAJIl'.'TEAD. 
Longitude W. .... 0 34 
Latitude 52 45 
Height above sea, 370 feet. 
Years. 
Bain. 
1854 
24-0 
1855 
30-5 
1856 
30-0 
1857 
29 '2 
1858 
22-5 
185!) 
33-0 
1860 
36-2 
1861 
24- 1 
1862 
29-5 
1863 
26-7 
Average 
28'5 
Mean 
Temperature 
45'6 
47- 7 
49-G 
48- 3 
49- .", 
45-7 
48-0 
48-4 
\ 9 ' ( I 
47-1 
Hemi;l Hehpsthad. 
o ' H 
Longitude W. 0 27 50 
Latitude . . 52 45 0 
Height above - sea, 250 feet. 
Rain. 
18-2 
25 '8 
26- 6 
28-1 
20-5 
32 Mi 
342 
22 ' 2 
27- 4 
22-7 
Dal tons 
Gauge. 
1 4 
.V4 
7- 4 
7'4 
32 
4-5 
12-1 
64 
8- 0 
3-3 
•9 
ROYSTOX. 
o / II 
Longitude AV. 0 0 2 
Latitude . . 52 2 40 
Ileigbt above sea, 2CC feet. 
Rain. 
Mean 
Temperature. 
18- 1 
25-0 
21-9 
27-9 
20-4 
25-4 
29-5 
19- 8 
23-9 
17-8 
22-9 
49- 2 
46-7 
48-8 
50- 5 
48-9 
50 ' 2 
46 -O 
48- 5 
4S-5 
49- 4 
48 '6 
Aeea and Population. 
The geographical extent of the county may be taken to be, in 
length, south-west to north-east, 36 miles ; south-east to north- 
west, 2G miles; with a circumference of from 130 to 140 miles. 
Halley is quoted as estimating its superficial area at 451,000 
acres. The population returns 1861 give it at 391,141 acres. 
Clutterbuck gives the population, in 1801, 97,577 ; 1811, 111,654: 
increase, 14,077. The last returns, 1851, 167,298 ; 1861, 173,294: 
increase, 5996. Total increase since 1801, 75,717. The persons 
employed chiefly in agriculture in 1801 are 20,611. The fami- 
lies so employed in 1811, 16,998. 
Maekets and Sales by Auction. 
Of* the old markets, suffice it to say, that there are 18 market 
towns in which the old system of selling wheat by the load of 
5 bushels is still very generally followed. Barnet fair is still 
