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ures? Explain: "Lime enriches to-day, but impoverishes to-morrow"; "Lime, and lime without manure, makes both farm and farmer poor." (5.) To test for Sourness in Soils: —Add some of the soil to a jar of water, and shake. Allow to settle and stand for a day 7. Test with litmus paper. The rapidity and extent of the reddening of the litmus paper is an indication of the acidity of the soil. The amount of fresh lime necessary to restore blue to the litmus might be taken as a further test of the sourness of the soil. A lump of the soil added to purple-cabbage water and allowed to stand for a day will also give a good test. If the purple-cabbage water around the lump of soil is turning red, the soil is sour, and the extent of the reddening indicates the amount of acid present. What plants thrive on acid soils? Are they of any economic value? What colour are the stems of most acid plants? Is this an acid colour? To what extent may plants be looked upon as soil-indicators'? (6.) To test for Alkalis in Soils: —Proceed as in the acid-test above, remembering that alkalies turn litmus blue instead of red, and turn purple-cabbage water green. This test will be of little practical value in New Zealand, as most of the soils are either volcanic (hence acidic), or decomposed acidic rocks, such as pumice, obsidian, rhyolite, trachytic pumice (scoria?), trachyte, and andesite (blue metal). However, near the sea, and around such inland arms of the sea as the Manukau and the Waikato, excess of various salts will be found. Test. Account for the black turf on a whitish subsoil near the sea and around tidal rivers and ocean inlets. What is the colour of foreshore muck and tidal mud-flats? Add some washing-soda to a green compost made of crushed leaves and herbs, fibrous roots, and grass. Sprinkle with water occasionally. Examine in a fortnight. What is the colour of the compost? Has any decomposition taken place? Sodium-carbonate (washing-soda) is often called "black alkali" in arid or semi-arid districts. The addition of sulphate of lime (gypsum, plaster-of-paris, land-plaster) to " black alkali " (washing-soda) changes the latter to " white alkali " (sodium-sulphate), which is much less injurious to plant-life than the "black alkali." Of course, the excess of any alkali is injurious to vegetation, as well as to tilth, causing crusting, puddling, and hard-pan. Place a little common salt in the bottom of a glass tumbler, fill with wet sand, and allow to stand in the sun for a few days. What causes the whitish crust to form? Expose some sulphate of potash in an open paper sack for a time. What causes the sack to become wet, and the salt to become soft and sticky? What happens to table-salt in wet weather? Not only are alkalies very soluble, but most of them have a great affinity for water — i.e., deliquescent. This property of absorbing moisture makes limited amounts of such salts valuable conservers of soil-moisture, but excesses of them causes puddling, or stickiness of soils. Excess of muriate of potash in potato-manures even causes clamminess in the potato. As bulbs prefer cold wet ground, excess of sulphate of potash is often added to conserve the soil-moisture. One ounce to the square yard would be considered an excess, and might make the soil too clammy. What plants grow on alkaline deserts and salty places ? What trees thrive near the New Zealand coast? What plants are found growing in the sand along the New Zealand coast? To what family do most of them belong? Saltbush, New Zealand spinach, fat-hen (lambs-quarters), atriplex, and Russian thistle, so common along the sea-coast, are much alike in habit, taste, flower, and seed. They belong to the goosefoot family, which has an ancestral liking for salt. Most of them have a salty taste, and are adapted for living in hot, dry, arid places. Beets and mangolds are members of this family, and hence salt is commonly added to the soil as a necessity to their growth. Such plants are called halophy 7 tes, or salt plants. Sprinkle a handful of salt on a square yard of healthy clover turf. Note the effect. Explain. What is the great disadvantage in using salt as a weed-killer? How can excess of alkaline salts be removed from soils? What manures would have a neutralising effect on alkaline manures or alkaline soils? What is the chief difference between superphosphate and Thomas's phosphate? How is the former made "super" and the latter "basic"? How does basaltic rock differ from volcanic rock? What will be the nature of residual soils formed by the disintegration of coral, sea-shells, chalk, or limestone? What would be the best manures for such soils? (7.) The test for phosphoric acid in soils is too complicated to be recommended for public schools. Since one-tenth of 1 per cent, phosphoric acid is considered a good percentage in soils, and since the most .careful handling of ammonium-niolybdate, nitric acid, and ammonia is necessary to detect it, it is readily seen why 7it is not recommended, valuable as it might be to know the need of a soil for this essential element of food-plant. (8.) Mechanical Analysis of Soils: —To make apparent to the eye the composite character of soils, (a.) Put a sample of the garden-soil in a specimen-tube, fill with water, and shake thoroughly. Quickly stand the tube erect and allow to settle. Retain it as a permanent record of the water-gravity separation of the soil into its component parts. Visit a little stream, and show that the stream also separates in like manner the soils it passes through. In like manner the river, on a large scale, analyses the soil of its drainage-basin. Where are the coarse gravels deposited? The coarse sands? The fine sands? The silts? The clay sediments? What soils compose alluvial fans and deltas? In reality, which are the heavier soils—clays or sands? A cubic foot of dry sand weighs from 1051b. to 1101b., and a cubic foot of dry clay 70 lb. to 80 lb. What is meant when we speak of " heavy " clay soils and " light sandy soils " ? (b.) Arrange in a series directly above each other a large glass beaker, a fine coffee-strainer, a medium coffee-strainer, and a coarse coffee-strainer respectively. Pulverise a large tablespoonful of garden-soil or other sample to be analysed, and place it it in the top and coarsest sieve. Gently add water from above, which will quickly pass through each strainer in turn to the beaker below, carrying with it such particles of soil as will pass through each mesh. Keep the deposits in the strainer well stirred, and allow water to pass through till it comes forth clear at the bottom, and empty the lower beaker as it fills into other beakers, which are allowed to stand and settle. The top coarse' sieve will retain only small gravel and bits of roots, humus, itc. The next sieve will retain only the coarse sand, and the finest sieve will retain only the fine sand. The clays will pass through and settle down as sediments in the bottoms of their respective vessels in order of coarseness. These six or seven component parts may be removed to a sheet of