The recent frosts have admonished all amateur and professional horticulturists to remove all plants intended to be cuI. tivated in the green house or conservatory during the winter, from their beds to pots. We find in TiZtoft's Journal of Horticulture, a very seasonable article, from the pen of Wm. F. Channing, M. D., on the care of “ house.plants,” which will be of great service to' those who have neither green-house nor conservatory, and who, notwithstanding, desire to preserve and enjoy the companionship of their summer favorites. ” How to make plants grow in the house is a much more important question than how to make them grow in the greenhouse. Few persons have conservatories. Almost every per. son has a window at which the spring and summer of plant. lite may be fostered and maintained during the long winter months. ” Formerly almost every house had its plants. The children and the flowers were the chief ornaments of the old homestead. Durin g the last generation, or since the introduction of furnaces and gas, the cultivation of plants in our houses has steadily declined. I propose now to show that th is great depriva ion and loss to our modern houses is unnecessary, and that plants may flourish as well under the dis;:ensation of gas and the furnace as in the days ot the old wood.fire and mold-candles. ” It may be true that plants will not grow in an artificially desiccated air. The skin and the delicate membranes of the throat and lungs parch in the dry furnace heat just like the leaves of the plants. The freshest complexion becomes wizened by a winter of this sirocco. What then shall be done in our furnace-heated houses ? Simply introduce evap. orators, which shall furnish to the air at least one-half as much moisture as the air naturally contains at the same temperature in spring or summer, The shrinking of the wood. work of the houses, or warping of furniture, are indications of an unnaturally dry heat, which is fatal to plant, and inju. rious to animal life. ” It is true also, that plants will not thrive in close rooms, charged with the sulphurous acid escaping from the com. bustion of anthracite or a product of combustion of im. pure illuminating gas; and in the same atmosphere the throat and lungs of human beings will suffer more or less severely. What is the remedy ? Open a ventilator into the chimney, near the top of every room, if you can do no better, 'and keep it open, at least during the evening, whfe the gas is burning. ” I am prepared to say that furnace-heat and gas-light are no obstacles to the cultivation of plants, observing only the precautions which are equally essential to human health. I think the rule should be broadly stated, that any room in which plants refuse to grow is unfit for human life. ” In this connection, it is proper to enter a protest against the barbarous habit of excluding the sunshine from inhabited rooms, especially in winter. Its effect is almost as depressing on children and delicately organized women as upon plants. ” There is one other obstacle to the growth of plants in the modern house; which is the plague of insects. Some varieties, especially the mici oscopic red spider, are uncontrollable in a dry atmosphere, but retire at once before proper evaporation. For the rest improved resources of which I may speak at another time, make it toterably easy now to keep house. plants free from parasites. ” To illustrate theory by fact: I heat a moderate sized house, containing about twenty thousand cubic feet, with a furnace. I find it necessary to expose seven square feet of evaporating surface in the air chamber of the furnace to produce a proper degree of atmospheric moisture. Half this surface would answer with better exposure. About a pint of water is evaporated in twenty.four hours for each seven thousand cubit feet in the house, in raising the temperature from 40° to 70°, two pints in raising it from 30° to 70°, three pints in raising it from 20° to 70°, and four pints in raising it from 10° to 70°, and about five pints in raising it from zero to 70°. Thus, in the extremest of cold weather, it requires nearly r.ix pails of water in twenty-four hours to keep the atmosphere of the house soft and agreeable though not appreciably moist; that is, not nearly as moist as the ordinary summer air at- 70°. ” At twelve windows north, east, south, and west of the house thus heated, I have about seventy plants, mostly of the common kinds in very fine condition. During several years I have never known them to be injured by the furnace-heat and never by the gas, freely consumed, except in a single in. stance of an ivy growing near the ceiling of the room during an accidental leaking of gas. ” I find that ivies thrive peculiarly under the conditions described, growing well in positions furthest from the light; as, for instance, on the hearth, forming a magnificat fireb0ard. Six or eight varieties of variegated leaved ivy thrive well' with the common. I find that roses which have blossomed during the summer in the ground, being potted after hard frost, stripped ruthlessly of every leaf, and trimmed in aim0st to bare poles are covered with buds within a month .a.t my window, and blossom all Wbter, great authorities to the con trary notwithstanding. This winter a Madame Bosanquet has left all the r st. showing buds in three weeks, closely followed, however, by the Agrippina Souvenir de Desire, Sarfan0, Hermosa, and Sangui nea. ” The Chinese-primrose, and coral-drop begonia are never out of blossom with me in the winter. A heliotrope, occupying a whole window, gives hundreds of its clusters, beginning in December. The orange, lemon, myrtle, and diosma grow with the greatest ease ; and the Daphne odora and laurusti- nus blossom in their season. Among other plants which I find it good to have in the house, I will mention the varieties of winter and spring blooming cactus, geranium, oleander, abutilon, calla, Tradescantia zebrina (large and small leaved), hoya, maurandia, tropreolum, saxifrage, Coliseum vine, Ma- deria vine, and the usual bulbs." [We would add to the valuable suggestions of Dr. Channing that a most excellent plan r( commended by an accomplished florist, and used by us with great success, is to saturate sponges with water and place them upon plates around and among the plants and underneath the stand. A liberal use of these greatly assists in neutralizing the effects of dry heat.—Eds. The New Thames Tunnel-How the Work Is Car- Ned On. The new Thames Tunnel has progressed so fast since our last notice, that it may now be said to be virtually complete, and will, it is expected, be in a fit state for opening for public traffic about the middle or the end of next month. The whole length, from what may be called the summit of Tower Hill to the end of Vine gt., in Tooley st, on the south side of the river, is j ust 1,320 feet, and of this distance more than 1,280 feet has already been accomplished and completed. Only about forty feet remain to make the j unction with the Tooley st. shaft. This short distance, at the rate at which “the tunnel has advanced, could be accomplished in about four or four and a half days, but the shaft itself cannot be ready within that time, nor, indeed, is it likely to be ready within the next fortnight. The shaft in Tooley st. is not so deep IUl that at Tower Hill by two ft. The former is to be fif y-eight ft., whereas the Litter is sixty ft. Yet the Tower Hill shaft was sunk quickly and without the smallest difficulty, for, after passing through about twenty ft. of made earth, the clay was reached, a little below, and not a sign of water was detected. What we may call the Tooley st. shaft is a litttle over ten ft. diameter, and has been sunk to a depth of about twenty ft., where it has come upon a bed of gravel,in which the water is more abundant than could be wished. It is not, however, in sufficient quantity to prevent the shaft being very easily kept dry by means of pumping,but pumping is by no means wished in this case, for the shaft is near some very large buildings, and to pump out much water from beneath them would Lave the effect of causing their foundations to sink rapidly as the gravel beneath them was diminished in bulk. as the water was drawn off. The Tooley st. shaft, therefore, is being sunk by means of a peculiar screw, which is called a “ miser,” an instrument used in works of this nature, and which brings up the maximum of gravel with the minimum of water. In this way the works are progressing steadily. As far as this shait has yet gone, it is double lined with iron casing, the inner rim of iron keeping out the leakage which may find its way through the joints of the outer. These iron rings of the shaft are four ft. deep each, and they are forced, by weights, down into the soil before much dredging out within their circumference is attempted. The double iron lining to this shaft will not, it is expected, be continued to a much greater depth than it is at present. There is every sign that the water-bearing stratum has been nearly passed, and that the cll1y will soon be reached. When this is attained, only one lining of iron rings to the shaft will be used to within a few ft. of the bottom, where bricks, faced with glazed tiles, to reflect the light, will be employed, as in the shaft on Tower Hill. Night and day, every four hours, the shield driving the tunnel,moves forward eighteen inches, so that there is an advance of nine ft. every twenty-four heurs. The manner in which this rapid advance is accomplished is as simple and ingenious as it is safe and quick in its mode of operation. The shield is a disk of mixed wrought and cast iron, weighing about two and a half tuns. In the front next to the clay, it is concave ; in the rear, where the men work, it looks like a gigantic cart wheel, having six spokes and an enormous open hollow felly in the center. To this shield, and extending backward over the men at work, is a powerful- iron rim, just like the cap to the end of a telescope. Thus, the miners wh'J work it excavate enough clay t1Jrough the center opening to enable one man to pass in beyond the tace of the shield, and he soon cuts away clay enough to find room for two, and when a comrade joins him, there is son room made enough for three workers, but seldom for more. The clay is of the kind well known as the stiff London clay, of a blackish green color, just moist enough to give it a thorough tenacity, but without any water. When about two feet have been ex' avated all round in front of the shield, the miners return back through the central hole, and, with ordinary hand-screws, they force the shield on to the length of the distance they have excavated, its long rim still keeping them under shelter as it is advanced. Within this rim a segment of the iron tunnel is at once built in three segments, eighteen inches long, and so on, the process is repeated over and over again. The inner face of the shield is 80 instructed as to receive the pressure of six screw-jacks—one - in each of the six spokes we have spoken of. By these means a pressure of sixty tuns could be brought to bear on the whole shield. As a rule, however, one screw-jack and one man is sufficient to move it forward, and this with ease. In case of nny water being come to—such as a upring—for the whole tunnel is far ,ilow the bed of the river water—it would give indications of its pres 3nce in the moisture of the clay long before the miners reached it. In the course of the excavations of the shield, about 2,000 cubic yards of the London clay have been dug out for the tunnel alone. This, as fast as i t was cut out, was run out in little “ trolleys,” to the Tower Hill shaft, and hoisted up to the outer air. But every “ trolley “ dropped its quantum in the tunnel till the base of the tube became covered with some six or seven inches of sticky, wet clay. , This has all been removed, and the tunnel, as far as it has gone, is now clean from end to end. The result is, that all that passes on the river over head is ten times more distinctly heard than ever. The passage of a steamer is heard with a noise so loud and vibrating in the at present confine 1 air of the tunnel, that it is only the knowledge of the unalterable and almost immovable strength of the structure in which you stand that gives the hearer confidence. Not only can every vessel be heard passing—we speak of course of steamers, large or small—but even such slight noises as hammering on the ships in the Pool above can be distinguished not only by the sound, but even by the slight though perceptible vibration of the air. Yet, the whole tunnel is not only water-tight but air-tight. The tests taken for deflection, or any settlement in the iron tube, since it has been built, give results that show a stability that apparently nothing but an earthquake can unsettle. The greatest deflection was only one eighth of an inch from the true level, and in only two instances was it one sixteenth. As far as regards the tubes bearing pressure, they are equal now that they are formed in circles,to about ten times the pressure they can possibly have to bear, and to more than twenty times th” pressure that is now laid on them. Altogether about 864 rings have now been laid and bedded in with blue lias cement. About twenty more rings will complete the entire tunnel from Tower Hill to Tooley st. The descent down the shafts will be.y means of lifts. These are to be constructed on a special design of Mr. Barlow's, so as, in case of accident, such as the giving way of any of the apparatus, to clip the guiding rods and check the progress of the lift in a few feet. This invention, in fact, is only a very clever break, which, instead of acting instantly, and with a sudden jerk, as bad as a fall, slowly brings the lift to a stand still in about ten ft. This arrangement has one fspecial merit, which is, that it is never likely to be called upon ; for the wire rope which is to raise and lower the lift is to be about fifty times stronger than its supposed strain ,so that there seems very little chance of its breaking with the weight of ten people, when it has been tested t:J bear more than the weight of a hundred. The lift is to be a mere little iron room, built to hold ten people with comfort, though, from the ample space intended to be allowed, it might hold twelve with almost equal ease. The omnibus at the foot of the shaft is to hold fourteen. The time of transit from Tower Hill to Tooley st. is to occupy three minutes, and the fare is to be a penny.—io?idon Times.
This article was originally published with the title "The Care of House-Plants"