If sufficient sawdust, or peat, or dry earth be provided for a double charge, so that one charge may be drying in a shed while the other is in use, my belief is that this might be used for indefinite periods.
A final question, and one of very great importance, is the ultimate destination of the absorbent material.
Sawdust has a very bad reputation with agriculturists, who assert that when used in large quantities it grows fungi and poisons the land. If fresh sawdust be used, and if it be employed in relatively large quantities, and especially if it be buried too deeply, I can well understand that it would prove prejudicial to crops.
Fig. 21.—Dry Urinal.
I can positively assert, however, that deal sawdust or peat, after being soaked with urine, shows no disposition whatever to become mouldy. I have never seen mould upon deal sawdust, but I have seen it upon oak sawdust.
My experiments further show that when sawdust or peat has been used as a top-dressing good crops have followed, whether on grass or garden ground. The cricket clubs which have, in accordance with my advice, put up dry catch closets and dry urinals have used the products as a top-dressing at the end of the season, and with the result that their wicket pitches have been the envy of their neighbours.
Chemists tell us that urine is of high manurial value because of the large amount of nitrogen which it contains. This is doubtless true, but we all know that the immediate effect of pure urine is fatal to herbage. Whether this be due to the heat of the fresh urine or the salts, I do not know, but I fancy the latter. In the same way we know that a sprinkling of salt, or salt and water, kills weeds; but we are told that salt is a bad weed killer, because it ultimately acts as a manure, and causes increased growth. Now urine does the same thing.
The farmer who uses the urine and dung of his animals mixed with absorbent material (generally straw), and ultimately places it on the land as a top-dressing, gets nothing but good from it.