1910 Sept. 24th 15 1/2 inch 17.5 12.25 3 inches 12.5 11.75 6 inches 12.25 11.5 Oct. 5th 17 1/2 inch 17 15.5 3 inches 16.7 15 6 inches 15.5 14.5 Remarks. Sept. 24th: Warm day after a rather cold spell. Oct. 5th: After a long spell of dry, warm weather. The untouched plot had become smothered in weeds and could no longer be used for this experiment. The mulched soil is, however, cooler even than the hoed soil, and our expectation that mulching would keep the soil cool has turned out to be correct. {88} [Illustration: Fig. 42. Soil sampler. (See p. 82 for description)] It may be expected that the hotter soil--the unhoed plot--will also be drier than the others, and this can be found out by a simple experiment. Take a sample by making a hole six indies deep with straight and not with sloping sides: this is best done by driving a tube two inches wide into the soil (Fig. 42): if you have not got such a tool you may use a trowel, but you will have to be very quick and very careful. Weigh the soil--or a part of it if you have got a great deal--then set it to dry in a warm place for three or four days. Weigh again when it is dry: the difference gives the loss of water: find what it would be in a hundred parts. Our results were:-- {89} Date Percentage of water in the Untouched soil Soil hoed once Soil hoed three weekly times weekly 1910 June 4th 21.1 19.5 17.9 June 20th 14.7 16.0 16.0 June 27th 19.3 18.4 20.5 Remarks. June 4th; The weather is still cold and the summer has not yet begun. June 20th: Hot day following on some hot, dry weather. June 27th: Rain had recently fallen. When hoeing is done in the early part of the summer it dries the soil, and the more frequent the hoeing the drier the soil (see June 4th results). But later on, when the hot weather begins, the hoed soil loses much less moisture than the untouched plot; the latter lost 6.4 per cent. in 16 days in the top six inches, whilst the soil hoed once weekly lost 3.1 per cent., and the one hoed three times weekly lost only 1.4; the two hoed soils are now equal, and are both moister than the untouched soil. When more rain comes they get just as wet as the others: hoeing does not prevent water from sinking in, but it does prevent water from getting lost.