18 
cally reacting on the sodium carbonate would transform it 
into an inactive salt, is necessary, and is readily found in ; 
gypsum or sulphate of lime, which by a mutual shuffling 
or interchange of the basie and acidic elements, become 
respectively carbonate of lime or limestone and sulphate 
of soda or Glauber’s salt. The gypsum, moreover, renders 
insoluble the humus taken up and dissolved by the car- 
bonate of soda, and thus retains it in the soil. 
3. The injurious substances having been neutralised, it is essen- 
tial to reduce the surface evaporation which would tend te 
accumulate on the surface layers the soluble salts sucked 
up by means of capillary attraction. This is best effected 
by means of deep cultivation, frequently repeated, and by 
growing crops which root deeply and cover the ground, and 
also salt-loving plants such as plants of the cabbage and 
of the beet tribe or such plants as asparagus, saltbushes, 
and a variety of others. By such means the successful and 
profitable cultivation of the soil would, in mild cases, be- 
come feasible. 
Besides neutralising the injurious effects of the carbonate of 
soda, gypsum has a correcting effect on the physical conditions of 
the soil, which often becomes glutinous and forms a clayey hardpan. 
It coagulates the glutinous substance formed by the carbonate and 
destroys the puddled condition of the clay, thus enabling the roots 
to penetrate and the waters to drain through such soils. 
Limits oF SALT In WATER. 
Where irrigation is contemplated it is advisable to have it chemi- 
cally tested, if the water available is from under the surface or from 
pools or lagoons and is brackish to the taste. 
It is generally considered that the maximum of salt which arable 
soil should contain is equivalent to .03 chlorine. 
As regards water, the amount of chloride of sodium in potable 
water for continuous use should not exceed :— 
For human consumption, 50-60 grains per gallon, or 4oz. 
For irrigation, 100 grains per gallon, or 1oz. 
For horses and cattle, 480 grains per gallon, or loz. 
For sheep, 600 grains per gallon, or 1'0z. 
These figures, which are suggested by Mr. FE. A. Mann, State. 
Analyst, can, however, as he explains, be stretched within certain 
limits, thus: for irrigation a more highly mineralised water van be 
used provided it be applied only occasionally and to the roots, so 
as not to burn the foliage during the hot, or summer weather. Stock 
also, on sappy food, can stand more salt in the water. 
