68 CLIMATE AND RESOURCES OF 



first few years after irrigation with the produce of similar lands 

 which have been irrigated by canals ten or twenty years, and 

 also comparing the produce with the amount of seed sown in 

 these lands and in unirrigated lands. If it is found that the 

 produce and proportion of it to seed sown is less on land that 

 has been irrigated for some length of time than on land 

 recently brought under irrigation, it may safely be inferred 

 that irrigation is doing more harm than good to the country. 



I have shown how irrigation, by hardening the surface-soil, 

 acts injuriously on the climate by increasing the heat ; it also, 

 by hardening and condensing the soil, and preventing the 

 rain falling on the surface sinking into the ground, increases 

 surface-drainage, and assists the desiccation of the country by 

 the water in the soil being better able to rise in the condensed 

 soil by capillary attraction than in a soil not so consolidated. 

 The harder and more compact the soil becomes, the less 

 moisture is found in the subsoil, say one or two feet below the 

 surface, after a lengthened period of dry weather. 



The increase of indigo cultivation in the Upper Dooab, and 

 its successful prosecution there, is advanced as an argument 

 in favour of canal irrigation. Here is an extract of a letter 

 from an indigo-planter in that part of the country to another 

 indigo-planter on the subject : 



" The produce in canal-irrigated lands, in my opinion, will 

 be worse yearly ; what with sowing the same seed, and with 

 this constant cropping and flooding, the lands are being 

 thoroughly exhausted. I remark yearly a great falling off of 

 leaf, and this, by the bye, appears to be increasing. Canal 

 plant grows too quickly ; it is, in fact, forced, and it conse- 

 quently cannot draw sufficient support from the soil fast 

 enough to keep pace with its rapid growth. If I am right in 

 my conjecture, produce will get worse as the soil becomes 

 more exhausted/' &c. 



