The advantages to be gained by adopting Maclean's plan will be an incredible saving of time, labour, material, and, consequently, of expense, combined with a comparatively small waste of ice, thus putting within the reach of fishermen and others of limited capital, a cheap and useful means of conveniently storing and preserving any quantity of ice.
In preference to one or more largo houses, Maclean makes choice of several small ones - each of them capable of holding, say, about 20 tons - because he finds that, an ice-house once opened, its contents, exposed to the atmosphere, are more liable to waste than the ice in one which has not been opened. The advantage of adopting the smaller-houses will thus at once be seen; the opening of one exposes but a small.
Again, these houses can be rapidly lilted, and should one, through any cause, fail to serve its purpose, there arc others to fall back upon. These remarks apply to his own peat-houses only, which are constructed on the following principle, being the most useful to meet the requirements of his fisheries, which, previous to the extension of the railway to Oban, were difficult of access to the market. Having selected a peat-moss of the required depth, convenient to a road, and near the margin of a small sheltered lake, he marks out the ground to the dimensions shown on Figs. 7, 8, 9 for the interior of the house; the divots removed from the surface are placed in a circle round the edge of this space so as to strengthen and protect it during operations. Six men in a few hours ran make the necessary excavations: two are employed clearing out the space required for the storing of the ice; one to cart; one to assist in filling the cart from the debris, and two are employed in cutting the drains; a seventh man is simultaneously engaged in preparing the roof The space intended for the ice being completed, the whole of the men, except the one preparing the roof, join in making the drain. By the time the drain is half finished the supports for the roof are put up.
These are made of rough pieces of oak, and rest on barrel staves placed at the required intervals across the top of and at right angles to the wall. The spaces between the couplings are filled up with hazel or oak branches about 2 in. thick; a layer of divots, heather side inwards, is now put on; over that is laid a coating of the best and softest moss taken from the drain and tramped into a solid mass all over the roof to a uniform thickness of 15 in. After this, another layer of divots is put on, heather side out, and the whole is covered with straw or heather-thatch to the thickness of 2 in., and secured with heather-rope or coir in the usual way. The apex is protected from destruction by birds by covering it with a piece of old tarpaulin to the breadth of 15 in. The drains are dug 1 ft. below the level of the floor of the house. A hole is cut in the north side of the house to admit of a siphon being placed in it. Small drains, as shown in Fig. 7, are cut, and the siphon - which Maclean has found to answer well in the peat, and which is made of -indiarubber tubing 1-1 1/2 in.diameter, and lashed to a bit of iron bent to shape and served over with marlin - is placed.
It has a bell-shaped mouth-piece made of wood or metal, with a rose covered over with a small wooden-perforated box to protect It from injury. If, by age is coming from the house, or that the water is exhausted by evaporation, it is well to attach a small piece of leather over the nozzle of the siphon, which, when the wind blows against it, arts as a valve. A few branches placed in the bottom will keep the drains clean, and the filling of the house may at once be proceeded with. The ice should Always be broken up into as small pieces as possible, well packed, and salted with snow. When the house is filled to about 1 ft. above the level of the walls, pack the remaining space with sawdust.
As there are many places where peat cannot always conveniently be found, Maclean would, as the next best means of preserving ice, recommend it to be height into the ground, so as to enclose a sufficiently large space, and place them as close to one another as possible, any rough edges being previously cut off. Tie them inside and outside by strong rafters of the same material in a horizontal position - 3 will suffice inordinary cases; line the inside of the structure with rough sarking boards, filling up the crevices with sawdust well rammed in courses corresponding to the depth of the sarking boards all along to and underneath the baulks; thatch in the usual way with turf and straw or heather; put a coating of coal-tar outside the sides of the house, and give the floor a gradual slope towards the door; cut a drain round the outside to carry - away the surface water and any waste that may take place. A space of 1 ft. to be packed with sawdust should be left between the ice and the wall, and filled up gradually as the ice is being stored. The space immediately inside the door should be carefully and tightly packed with sawdust: the small door made in the larger one admits of this being easily done.
A house of this kind costs between 71. and 8/. The letters on the roof indicate as follows: - a, thatch; 6, turf; c, tramped peat; d, rough rafters.
(8) The old-fashioned plan of storing ice under ground was assuredly a good one, but had the disadvantages of occasionally being impracticable, from the character of the subsoil, and always expensive.
An ice-house, to be thoroughly efficient, need not be under ground. The chief requirements of such storage are that it be formed of non-conducting materials, so far as heat is concerned, and so constructed as to give easy access, and drainage, without unduly admitting the external air. Added to these, and the better to ensure an extended sphere of usefulness, low first cost must be mentioned.
These indispensables to the modem ice-house, in Ross's opinion, are happily not far to seek. In wood we have the first requirement admirably met, while its adaptability and cost leave nothing to be desired; and, if care be exercised in the selection of the kind of wood used, and in its subsequent preservation by an occasional coat of paint, it will prove to be by no means the ephemeral material many suppose. The sole remaining difficulty is the design of the structure. So far as surroundings are concerned, a shaded situation is preferable, but not indispensable; and as for the external elevation, it can be modified to meet the taste and purse of the owner. By adopting any of the many modifications of the circular form, the ventilation is the better assured, while the cost is not in any degree enhanced.
The entire floor, extending at least 1 ft. beyond the exterior of the walls, should be of thoroughly laid concrete, not less than 1 ft. above the surrounding level, attention being given to have foothold for the wall-posts and slope from the centre for drainage. By this form of floor we guard against excessive terrestrial radiation and vermin.
The walls can be raised with any required number of angles, and the structure may range from a pentagon upwards. They must be double, with an interspace of 18 in. at least, and of sound pitch pine, - the interspace to be filled with the most efficient and cheapest non-conductor we have, viz. sawdust. Two doors are needful, one in each wall, and they must fit pretty tightly. The roof must be lined internally on the couples, and the interspace filled with sawdust as before. Felt is preferable as a roof covering, and the apex of the roof must be of the "Lutther" class of ventilator. The whole exterior to have 3 coats of best silicon white paint. For drainage, surface gutters in the concrete, radiating from the centre, and having trapped termini debouching at the underside of the concrete.
The house finished, it has to be filled. This is best done by pounding down the ice, from whatever source derived, packing it closely in, and ramming it well together as it accumulates.
To use ice economically is at all times a desideratum, but so long as the stores secured in the country are meagre, economy in its use is imperative on all. For economical purposes in general, the modified "Tube Cold Chamber" answers all requirements best. Externally of wood, with a double wall, and door in the front side, it stands for ordinary family use about 4 ft. high on corner supports 9 in. high. The wall interspace is filled with sawdust, and internally it is fitted around the walls and raised roof with U-shaped tin tubes l 1/2 in. internal diameter, placed about 5 in. apart, and extending down each wall and across the floor. Each has a small tap at the lowest point and communicating directly with the outside for drainage. They are filled with pounded ice, and simply corked at the mouths, which project through the tops for convenience.
The bottom of the chamber is fitted with bottle-bins for wine, and the remaining space is shelved throughout. The shelves extend to and touch the tubes, but no farther, thus affording sufficient intercommunication for the equalisation of the temperature. Ventilation is provided by air-ducts secured with wire gauze at the bottom and extreme top of the cover. The upper ventilator can be protected by lapped cover raised 1 in. from the top.
This refrigerator also forms an extremely effective ice-bin for family storage of small quantities of ice. The tubes are of course not then required, and it is better to line the bin throughout its interior with best galvanised iron and to have trapped drainage in the bottom.
The cost of the ice-house, as described, for an hotel or large establishment, would not exceed 30/. For smaller families, from half that sum. The refrigerator, on a scale suited to the first-mentioned classes, would cost from 5/., smaller sizes, from 21. 10s. The bins for temporary storage from 10s. upwards.