Some enterprising individuals have put into practice the old motto that 'Out of evil cometh good,' by buying up the slaughtered hosts of rabbits, cooking their bodies, and preserving them in tins as an article of food, and preparing their skins for the market. Nearly half a million rabbit-skins were exported from Hobart-Town in 1874, valued at three thousand seven hundred and twenty-five pounds.
What has been done in Australia and Tasmania ought primâ facie to be as easily accomplished in New Zealand. So urgent, however, are the representations of the farmers—and so great the fear of the government, which derives a large revenue from the rents paid for land, that this source of income will fail, as the land threatens soon to become worthless—that it is proposed to supplement such measures by a state grant in aid of the war against the invaders, and by the introduction of natural enemies, such as stoats, weasels, ferrets, and hawks; and means have already been taken to send a few of our surplus stock of these invaluable animals from England. If ordinary measures of this kind are not sufficient to keep in check the inordinate increase of an animal which will reproduce itself a million and a quarter times in the space of four years, extraordinary means must be adopted.
[THE MONTH:]
SCIENCE AND ARTS.
'On the Transport of Solid and Liquid Particles in Sewer Gases,' is the title of a short paper by Dr Frankland, read at a meeting of the Royal Society. That particles of many kinds are constantly floating in the atmosphere, even at great heights, is well known. At times noxious or deadly particles are diffused among the mass, and disease and death are the consequence. Dr Frankland has proved by experiment that noxious particles can be conveyed long distances, and he sums up his conclusions thus: '1. The moderate agitation of a liquid does not cause the suspension of liquid particles capable of transport by the circumambient air, and therefore the flow of fresh sewage through a properly constructed sewer is not likely to be attended by the suspension of zymotic matters in the air of the sewer. 2. The breaking of minute gas bubbles on the surface of a liquid is a potent cause of the suspension of transportable liquid particles in the surrounding air; and therefore when, through the stagnation of sewage, putrefaction sets in, and causes the generation of gases, the suspension of zymotic matters in the air of the sewer is extremely likely to occur. 3. It is therefore of the greatest importance to the health of towns, villages, and even isolated houses, that foul liquids should pass freely and quickly through sewers and drain-pipes, so as to complete their discharge from the sewerage system before putrefaction sets in.'
The Birmingham Corporation sewage-works comprise a farm of two hundred and sixty-six acres in the valley of the Tame. The outflow of the two main sewers is treated with lime, which throws down the solid matters; and after the sewage has crossed a few tanks, the liquid portion flows into the Tame in a condition much less impure than the water of the river itself. The deposited sludge amounts to nearly four hundred tons a day. Great part of this is utilised by 'double-digging' of it into the land, three years being required to dig the whole farm. Another part is converted into Roman cement by General Scott's process.
The results appear to be satisfactory, for we are informed that 'the rye-grass grown on the farm averages from thirteen to fourteen tons an acre at each cutting, and several cuttings are obtained each year. After each cutting the land is immediately irrigated thoroughly with sewage, and in about three weeks the next crop is generally ready for cutting.'
At Manchester the Health Committee collect the excrementitious matters and other house-refuse in properly constructed vans, which are cleansed after each journey to the yard in the outskirts. There the whole mass is sorted; and what that sorting involves may be judged of from the fact that the quantity collected each week amounts to about three thousand tons, comprising 'paper, one ton; rags, three tons; dead dogs, cats, rats, guinea-pigs, and other animals, two tons; stable manure, seventeen tons; meat tins and old tin and iron, thirty-three tons; refuse from slaughter-houses and fish-shops, sixty tons; broken pots, bottles, and glasses, eighty tons; vegetable refuse, door-mats, table-covers, floor-cloths, and old straw mattresses, one hundred tons; fine ashes, one thousand two hundred and thirty tons; cinders, one thousand four hundred tons.'
In a communication to the Scientific and Mechanical Society of Manchester, from the Proceedings of which these particulars are taken, it is further stated that 'not only is patent manure produced, but disinfecting powder, mortar, fuel, and other useful commodities, all from the vilest refuse; and another matter for wonder is that all this abominable stuff is worked up with so little offensive smell arising from it. In addition to these works, there are workshops in which the Corporation make their own vans, pails, harness, and other requisite appliances for dealing with the new system of treating town-refuse.' No coal is bought: the cinders brought in furnish fuel enough for all the furnaces and heating apparatus, and for the 'destructors,' in which the absolute refuse which was formerly piled in huge heaps in different parts of the city, is burnt into harmlessness, while the heat is communicated to a neighbouring 'concretor.' 'The spent fuel,' we are told, 'is carted to the mills, and is there converted into mortar, a mortar too of the best description, as the samples of brickwork built with it abundantly testify.' Some of the most offensive refuse is passed through the 'carbonisers,' and 'is resolved into a perfectly harmless material.' From all this we learn that the art of keeping a town thoroughly clean may be made to occupy a high place among the useful arts.
The manufacture of iodine by distillation of seaweed, established a few years ago in the isle of Tyree and other parts of the West Highlands, still goes on, and as is stated, with tenfold increase. The selling price, which used to be 1s. 3d. per ounce, is now not more than 5¾d.