188 Italian Irrigation. 
The following illustration is given of the arrangement of a 
mar cite field : — 
ADAQrATHICK, OR JfAIX lERICATrMG CHAKNEI- 
6C0LAT0RE MAESTKE, OR IIAIX DRAIXAOE CI!ANXEL. 
SECTION ON a b. 
Ilirrli.rl I 1 
A B, Main Irrigating Channel. 
C D, Main Drainage Chiuiiicl. 
E F, Minor Irrigating Cliannels, generallj- 12 inches wide, and C or 7 deep. 
G H, Minor IJrainage Channels, about half the aljove dimensions. 
A provision for drainage is of course made at the base of ejjch. 
slope, in a manner familiar to us all ; but the value attached to 
the surplus waters, colatori, is more of a novelty. These, "having 
passed over lands richly manured, have a value often considerably 
superior to their original one." Their temperature becomes 
higher as they How, partly from mechanical, and partly from 
chemical causes ; it being customary to apply to the upper 
meadows the richest manure, which is supposed to raise the 
temperature of the water, a point much insisted on for winter 
meadows. It is thcMefore calculated that water, before it is 
exhausted or dismissed from service, will have enriched double 
the area of the meadow which it first supplied ; and the surplus 
