Sluicing

“ In October, or after, draw the sluice of the first made pond, and lay it as dry as possible you can. It may be the sluice, especially if the pond be many acres, will not vent the water suddenly. That is of no great import, because, as the waters fall, you will have opportunity of fishing with nets, and so clear the fish by degrees; which left to the last, will be too great a burden to clear, and will not be done without damage; besides, the hurry will disorder every thing. If the sluice will not vent all the water from the pan, a labourer or two will soon throw it out with scuppets. ”

“ A sluice is where water is made to run through a ditch into a trough that has cleats nailed across the bottom to check the water and form ripples. Into this the pay-dirt is shoveled, and the water flowing through it leaves the gold at the bottom and carries the dirt away. ”

“ Ground sluices are natural gullies, answering the purpose of wooden sluices in localities where water is abundant for short periods only, and the construction of permanent sluices would not be judicious. In river mining, the current of a stream is turned aside, and sluices are erected in its bed for washing the dirt there accumulated. ”

“ The slug will devour almost any garden plant, whether it be a flower or a vegetable. They lay lots of eggs in old rubbish heaps. Do you see the good of cleaning up rubbish? The slugs do more harm in the garden than almost any other single insect pest. You can discover them in the following way. There is a trick for bringing them to the surface of the ground in the day time. You see they rest during the day below ground. So just water the soil in which the slugs are supposed to be. How are you to know where they are? They are quite likely to hide near the plants they are feeding on. ”

“ When I thought that for weeks past, this, my garden, had been providing them with sustenance, I was moved to fury. But I did not lose my head. There is a right way and a wrong way of doing everything. There is even a right way of killing slugs.
I have read in books that the gardener takes the slug and crushes it under his heel on the gravel path; a jobbing gardener might possibly do that—jobbing gardeners will do anything. Any man who does that is not fit to have a garden. He is only fit to collect house refuse in an open cart during hot weather. ”

“ Exclusive of animal decay, we can hardly arrive at a more absolute type of impurity, than the mud or slime of a damp, over trodden path, in the outskirts of a manufacturing town. I do not say mud of the road, because that is mixed with animal refuse, but take merely an ounce or two of the blackest slime of a beaten footpath, on a rainy day, near a manufacturing town. That slime we shall find in most cases composed of clay (or brickdust, which is burnt clay) , mixed with soot, a little sand and water. ”

“ Ordinarily the sluice runs only during daylight, but in some claims the work continues night and day. Cleaning up occupies from half a day to a day, and therefore must not be repeated too often, because it consumes too much time. In some sluices the cleaning up does not occur until the riffle-bars have been worn out or much bruised by the wear of the stones and gravel. ”

“ But during the winter, when the stream-banks are embossed in snow, and the streams themselves are chilled nearly to the freezing-point, so that the snow falling into them in stormy weather is not wholly dissolved, but forms a thin, blue sludge, thus rendering the current opaque—then he seeks the deeper portions of the main rivers, where he may dive to clear water beneath the sludge. Or he repairs to some open lake or mill-pond, at the bottom of which he feeds in safety. ”

“ The slug, called Succinea, is not strictly aquatic, but lives in damp places, and may be seen in full activity far from rivers, in meadows, where the grass is wet with rain or dew; but shells of the genera Limnea, Planorbis, Paludina, Cyclas, and others, requiring to be constantly in the water, are extremely exceptional in the loess, occurring only at the bottom of the deposit, where it begins to alternate with ancient river-gravel, on which it usually reposes. ”

“ When water is wanted, the sluicer raises the sluices more or less, as required, as a cook turns the cock of a fountain, and closes them again carefully at night; otherwise the water would flow into the canals, then overflow them, and inundate the whole country; so that even the little children in Holland are fully aware of the importance of a punctual discharge of the sluicer's duties. The boy was about eight years old, when, one day, he asked permission to take some cakes to a poor blind man, who lived at the other side of the dyke. ”

“ Then again, if the day be wet, the slug works by day as well as by night. It is the sun and drought that he shuns, and not the light. Therefore the only effectual way to destroy slugs is to sow lime, in dust, and not slaked. The slug is wet, he has hardly any skin, his slime is his covering; the smallest dust of hot lime kills him; and a few bushels to the acre are sufficient. You must sow the lime at dusk; for then the slugs are sure to be out. Slugs come after a crop that has long afforded a great deal of shelter from the sun; such as peas and vetches. ”

“ Kinnicutt, Winslow, and Pratt in their book on Sewage Disposal state:
With an average depth of 10 inches per dose of sludge of 87 per cent water content, one square foot of covered (glass) bed should dry to a spadable condition one cubic yard of sludge per year.
500The sludge is run on the bed in small quantities at periods from two weeks to a month apart. In favorable weather Imhoff sludge will dry in two weeks or less to approximately 50 to 60 per cent moisture. It is then suitable for use as a filling material on waste land, for burning, or for further drying by heat. ”

“ Where skins are used, as in Brazil, they may be dried and beaten over a cloth, placed to receive the fallen particles. Sluice washing is generally carried on during the day only; but when water is abundant and cheap, the work may be continued throughout the whole twenty-four hours. The sluices are cleaned up once a week, or more seldom, according to the rate at which gold and amalgam accumulate. ”

“ I kill some things that other things may live. They cannot all have it their own way in my garden, and I must settle which side is to prevail. All the same, I do sometimes try to look at it from the slug's point of view. What does the slug think about it? Let us hope and believe that the slug does not think about it.
With what brutality, too, does the gardener fight against the prolific impulses of nature. The dead flowers must be picked off from the sweet peas; otherwise they give up work early. If you cut down the lupine spikes as soon as the beans have formed, you will get more spikes. ”

“ When the heavy rains of spring and fall occur, the effluent water from those slopes is dilute sewage, dilute human excrement, and, especially if the land has been recently ploughed, a large quantity of the surface-soil, and with it the freshly-applied human excreta, and the remaining noxious parts of the previously-applied batch of filth still present in the soil, must necessarily be, and is, washed down-hill and into the water-supply of the town. ”

“ A little muddy water trickles through the line of sluices. One of us goes to the reservoir, a few hundred yards off, and turns on the water. Another goes to the tail of the sluices with the sluice-fork. Then is heard the clicking of the pick and the grating of the shovel against the red dirt; down comes the muddy water over the bank and the day’s work has fairly commenced.
We stand in a row, allowing sufficient room between each for swinging the pick. We are undermining the bank, the water running at our feet and between us and the bottom of the bank. ”

“ When it is desired to remove the sludge deposited in the cone-shaped bottom of the tank, the sluice-valve on the sludge outlet is opened and the sludge is forced up by the head of water, due to the difference in level between the top-water level in the tank and the invert of the sludge-outlet. It has been stated that this method of sludge removal is subject to difficulties, due to the consolidation of the sludge in the cone, to such an extent that it becomes of too thick a consistence to flow up the vertical pipe. ”

“ The disposal of sludge is a problem common to all methods of sewage treatment involving the use of sedimentation tanks.
Sludge is disposed of by: dilution, burial, lagooning, burning, filling land, and as a fertilizer or fertilizer base. Certain methods of disposal, such as burning or as a fertilizer, demand that the sludge be dried preparatory to disposal. Sludge is dried on drying beds, in a centrifuge, in a press, in a hot-air dryer, or by acid precipitation. ”

“ The stones used are cobbles, six or eight inches through at the greatest diameter, and usually flattish. A good workman will pave eight hundred square feet of sluice-box with them in a day; and after the water and dirt have run over them for an hour, they are fastened very tightly by the sand collected between them. In large sluices, wooden riffle-bars are worn away very rapidly—the expense amounting sometimes, in very large and long sluices, to twenty or thirty dollars a day ”

“ As soon as the soot gets wet it is no longer a deterrent to slugs. Lime is also recommended to be used in the same way as soot; but it, too, fails to serve its purpose when it has once become damp.
Then have we no way to keep down the ravages of slugs? Yes!—we have one way, a very excellent way, but a most tedious and unpleasant one to carry out. The only effective way of thwarting the ravages of the slugs is to pick off by hand the culprits, while they are gorging themselves in the evening. ”

“ If a long trough, divided in the middle by a sluice or partition, have one end filled with water, and the other with quick silver, both fluids will remain quiet so long as they are divided, but when the sluice is drawn up, the heavier fluid will rush along the bottom of the trough, while the lighter, from being displaced, will rise, and flowing in an opposite direction, spread itself at the top. ”

“ In greenhouses a slug will forage night after night—as gardeners know to their cost—over the same beat, and will always return to the same hiding-place. Limax flavus has been noticed crawling with great regularity to a sink from a hole near the water-pipe, and keeping to a well-marked circular track. ”

“ Of course economy and convenience of working require that the sluice should be near the level of the ground, and as that may be steep or level below the claim, the grade of the sluice must to some extent conform to it. There are thus a multitude of points to be taken into consideration in fixing the grade of a sluice; but a fall of less than eight or more than twenty inches, in a box of twelve feet, would be considered as unsuitable for the board-sluice. ”

“ When barriers of lime, ashes, etc., are ineffective, traps consisting of pieces of board sacking and similar materials placed about the field prove inviting to the slugs. They collect under these and by going over the field in the early morning they may be put into a salt-water solution or otherwise destroyed. Arsenical sprays applied with an underspray nozzle to the lower surface of the leaves will help control the slugs. ”

“ At the mouth of nearly every ravine there are countless little mounds which marked the end, or dump of the sluice-box in the placer mining. When the mound got the proper height the sluice was simply lengthened, like putting another joint onto a caterpillar—and there you were! The sluice-boxes have long since been moved away or rotted to mould but the little mounds remain, to be mansions for hustling colonies of small black ants.
The country, in various localities, is pitted with prospect holes, and the hills are pierced with drift tunnels and abandoned mines. ”

“ The legitimate sport is the night hunt, the search, by the light of a lantern, of cabbage or lettuce leaves cast down in the favourite haunts of the slug. On these, on a warm night after a light rain, it may be found by the score—of all sizes, from the tiny glistening speck no larger than a pin’s head, to the full-grown animal as long and as thick as a man’s little finger. The slug-hunter recognises two species of slugs. There are others he knows, notably the great black slug of the woods, but these concern him not. ”

“ These animals attack the plants after nightfall, and during the day seek cover. Though slugs will shelter in the soil, they, together with snails, will shelter in any convenient place, such as under old boards, sacking, bricks and stones upon the ground, or under large leaves or amongst rank herbage—​indeed, in almost any place that affords cover and moisture. Slugs and snails are especially active during wet weather, and at such times, owing to the overcast conditions, they will continue their depredations in the daytime. ”

“ The slug is as defenceless as the pigeon, and no greater share of courage is required for slug hunting than for pigeon shooting; but whereas the one amusement is a slaughter of innocents, the other is the destruction of ravening beasts, and stands therefore in a far higher category. The slug trusts neither to speed nor fierceness; we know from story how his cousin, the snail, when attacked, put to flight a troop of tailors, by the exhibition of his horns, or, as the scientific would tell us, of his eyes on their upreared stalks. But if the slug possesses eyes, he makes no show of them. ”

“ The slugs, which commit their depredations in the night, creep under the leaves in the morning, and by turning up the leaves you come at the slugs, and crush them, or carry them away. But besides the immense daily labour attending this, the slug, in a field sowed with wheat, has a clod to creep under at every foot, and will not go five feet to get under a cabbage-leaf. ”