[72] In one of their Reports the Board of Health has spoken of the yearly cleansing of the cesspools; but a cesspool, I am assured, is rarely emptied by manual labour, unless it be full, for as the process is generally regarded as a nuisance, it is resorted to as seldom as possible. It may, perhaps, be different with the cesspool-emptying by the hydraulic process, which is not a nuisance.
[73] It was ascertained that 3 gallons (half a cubic foot) of water would carry off 1 lb. of the more solid excrementitious matter through a 6-inch pipe, with an inclination of 1 in 10.
[74] Mr. Rammell supplies the following note on the use of “Poudrette.”
“In connexion with this subject,” he says, “a few observations upon the application of poudrette in agricultural process may not be without interest.
“With regard to the fertilizing properties of this preparation, M. Maxime Paulet, in his work entitled ‘Théorie et Pratique des Engrais,’ gives a table of the fertilizing qualities of various descriptions of manure, the value of each being determined by the quantity of nitrogen it contains. Taking for a standard good farm-yard dung, which contains on an average 4 per 1000 of nitrogen, and assuming that 10,000 kilogrammes (about 22,000 lbs. English) of this manure (containing 40 kilogrammes of nitrogen) are necessary to manure one hectare (2½ acres nearly) of land, the quantities of poudrette and of some other animal manures required to produce a similar effect would be as follows:—
| Kilogr. | |
| “Good farm-yard dung, the quantity usually spread upon one hectare of land | 10,000 |
| Equivalent quantities of human urine, not having undergone fermentation | 5,600 |
| Equivalent quantities of poudrette of Montfaucon | 2,550 |
| Equivalent quantities of mixed human excrements (this quantity I have calculated from data given in the same work) | 1,333 |
| Equivalent quantities of liquid blood of the abattoirs | 1,333 |
| Equivalent quantities of bones | 650 |
| Equivalent quantities of average of guano (two specimens are given) | 512 |
| Equivalent quantities of urine of the public urinals in fermentation, and incompletely dried | 233 |
“M. Paulet estimates the loss of the ammoniacal products contained in the fæcal matters when they are withdrawn from the cesspools, by the time they have been ultimately reduced into poudrette, at from 80 to 90 per cent.
“I have not been able to meet with an analysis of the matters found in the fixed and movable cesspools of Paris, but in the ‘Cours d’Agriculture,’ of M. le Comte de Gasparin, I find an analysis by MM. Payen and Boussingault of some matter taken from the cesspools of Lille, and in the state in which it is ordinarily used in the suburbs of that city as manure. This matter was found to contain on the average 0·205 per cent of nitrogen, and thus by the rule observed in drawing up the above table, 19,512 kilogrammes of it would be necessary to produce the same effect upon one hectare of land as the other manures there mentioned. The wide difference between this quantity and that (1333 kilogrammes) stated for the mixed human excrements in their undiluted state, would lead to the conclusion that a very large proportion of water was present in the matter sent from Lille, unless we are to attribute a portion of the difference to the accidental circumstance of the bad quality of this matter. It appears that this is very variable, according to the style of living of the persons producing it. ‘Upon this subject,’ M. Paulet says, ‘the case of an agriculturist in the neighbourhood of Paris is cited, who bought the contents of the cesspools of one of the fashionable restaurants of the Palais Royal. Making a profitable speculation of it, he purchased the matter of the cesspools of several barracks. This bargain, however, resulted in a loss, for the produce from this last matter came very short of that given by the first.’
“Poudrette weighs 70 kilogrammes the hectolitre (154 lbs. per 22 gallons), and the quantity usually spread upon one hectare of land (2½ acres nearly) is 1750 kilogrammes, being at the rate of about 1540 lbs. per acre English measure. It is cast upon the land by the hand, in the manner that corn is sown.
“Poudrette packed in sacks very soon destroys them. This is always the case, whether it is whole or has been newly prepared.