e. Captain Lieurnur’s pneumatic plan. This process, the invention of a Dutch engineer, is in use at Amsterdam, Leyden, Drodrecht, and a few other Continental towns. It is also known as the ‘aspiration plan.’ Its outlines are as follows:—“The pipes and, tubes leading from the various water-closets and privies peculiar to the system are connected with street mains, which mains again communicate with underground horizontal cast-iron cylinders or tanks, these tanks being directly connected with a powerful air-pump worked by steam. Communication between the main and the tanks, as well as between the tanks and the pump, can be made or broken by means of stopcocks. Hence it follows that when access is allowed between one of the tanks and the air-pump, this latter will, when put into action, produce a vacuum in the tank, and if the stopcock of the main leading to the tank be then opened, the contents of all the privies and water-closets, the pipes of which run into the main,
will be removed by being swept into the tank by pneumatic force. In this manner each tank is treated in succession. Similarly the sewage is carried to the large reservoirs of a manure manufactory. It is here mixed with a little sulphuric acid to prevent the formation of ammonia, and being evaporated down in vacuo becomes converted, when sufficiently dry, into poudrette. In Lieurnur’s process all deodorants are dispensed with, and its mixture with water is prevented by means of porous drain pipes laid above the sewers, by which contrivance the subsoil water is kept out of the sewers.
Sewage, Utilisation of. “Mr Peregrine Birch read before the Institution of Surveyors a paper on ‘The Use of Sewage by Farmers,’ which embodied some facts that deserve to be noticed, as bearing on a question we have repeatedly discussed. It appears that there are at the present time ‘upwards of one hundred owners and occupiers of land in Great Britain who use sewage for the sake alone of what they can get out of it by agricultural means.’ Of these ‘more than sixty are tenant farmers, who continue to use it although they have, annually at least, the option of ceasing to do so,’ It seems five out of six of the tenant farmers purchase the sewage they employ, so that their adhesion to the method proves conclusively that it pays. Nearly four thousand acres of land are under regular cultivation with sewage. Mr Birch is of opinion that ‘advocates of sewage precipitation processes should not regard sewage farmers as their rivals, for a chemical process might be very largely used with advantage when farmers are being persuaded or taught to use sewage. But this should be the distinct aim of all cultivation, for there is no chemical process that could not be worked to greater advantage during two months of the year than twelve, or applied to a small quantity of sewage at less cost than to a large.’ Our primary interest is to see the utilisation of sewage generally adopted; the method employed must be determined by experience on the grounds of cheapness and expediency.”—Lancet.
SHAD′DOCK. A large species of orange, the fruit of Citrus Decumana (Linn.).
SHAGREEN′. This is prepared from the skins of the horse, wild ass, and camel, as follows:—The skin, freed from epidermis and hair by soaking in water, and, after dressing with the currier’s fleshing-knife, is sprinkled over, whilst still wet and stretched, with the seeds of a species of chenopodium, which are imbedded in it by strong pressure, and in this state it is dried; the seeds are then shaken off, and the surface rubbed or shaved down, nearly to the bottom of the seed-pits or indentations; it is next soaked in water, by which the skin swells, and the recently depressed surface rises into a number of minute prominences; it is, lastly, dyed and smoothed off. Black is given
to it with galls and copperas; blue, with a solution of indigo; green, with copper filings and sal ammoniac; and red, with cochineal and alum. Shagreen was formerly very extensively used for covering the cases of watches, spectacles, surgical instruments, &c.
SHALLOT′. Syn. Eschalot. The Allium ascalonicum (Linn.), a plant allied to the onion, the bulb of which is much used as a sauce or pot-herb.
SHAMPOO′ING. A practice common in the East, having for its object the increase or restoration of the tone and vigour of the body, or the mitigation of pain. It is applied either in the bath or immediately after quitting it, generally the latter, and consists in pressing and kneading the flesh, stretching and relaxing the knee-joints, and laboriously brushing and scrubbing the skin.
SHARPS. See Flour.
SHA′VING. The following are Mr Mechi’s instructions for this, to many persons, troublesome operation:—Never fail to well wash your beard with soap and cold water, and to rub it dry, immediately before you apply the lather, of which the more you use the easier you will shave. Never use warm water, which makes a tender face. Place the razor (closed, of course) in your pocket, or under your arm, to warm it. The moment you leave your bed is the best time to shave. Always put your shaving-brush away with the lather on it.