* It is manufactured by N. M. Lowe, Boston, and sold by him and J. Queen & Co., Philadelphia.

We will next notice the economy of time, labor, and expense secured by this cottage plan. The laundry work being done in the basement, all the cooking, dish-washing, etc., can be done in the kitchen and stove-room on the ground-floor. But in case a larger kitchen is needed, the lounges can be put in the front part of the large room, and the movable screen placed so as to give a work-room adjacent to the kitchen, and the front side of the same be used for the eating-room. Where the movable screen is used, the floor should be oiled wood. A square piece of carpet can be put in the centre of the front part of the room, to keep the feet warm when sitting around the table, and small rugs can be placed before the lounges or other sitting-places, for the same purpose.

Most cottages are so divided by entries, stairs, closets, etc., that there can be no large rooms. But in this plan, by the use of the movable screen, two fine large rooms can be secured whenever the family work is over, while the conveniences for work will very much lessen the time required.

In certain cases, where the closest economy is needful, two small families can occupy the cottage, by having a movable screen in both rooms, and using the kitchen in common, or divide it and have two smaller stoves. Each kitchen will then have a window, and as much room as is given to the kitchen in great steamers that provide for several hundred.

Whoever plans a house with a view to economy must arrange rooms around a central chimney, and avoid all projecting appendages. Dormer-windows are far more expensive than common ones, and are less pleasant. Every addition projecting from a main building greatly increases expense of building, and still more of warming and ventilating.

It should be introduced, as one school exercise in every female seminary, to plan houses with reference to economy of time, labor, and expense, and also with reference to good architectural taste; and the teacher should be qualified to point out faults and give the instruction needed to prevent such mistakes in practical life. Every girl should be trained to be "a wise woman" that "buildeth her house" aright.

There is but one mode of ventilation yet tried that will, at all seasons of the year and all hours of the day and night, secure pure air without dangerous draughts, and that is by an exhausting warm-air flue. This is always secured by an open fire-place, so long as its chimney is kept warm by any fire. And in many cases, a fire-place with a flue of a certain dimension and height will secure good ventilation, except when the air without and within is at the same temperature.

When no exhausting warm-air flue can be used, the opening of doors and windows is the only resort. Every sleeping-room without a fire-place that draws smoke well should have a window raised at the bottom or sunk at the top at least an inch, with an inclined shelf outside or in, to keep out rain, and then it is properly ventilated, provided the air outside is colder than the inside air - but not otherwise. Or a door should be kept opened into a hall with an open window. Let the bed-clothing be increased, so as to keep warm in bed, and protect the head also, and then the more air comes into a sleeping-room the better for health.

In reference to the warming of rooms and houses already built, there is no doubt that stoves are the most economical mode, as they radiate heat and also warm by convection. The grand objection to their use is the difficulty of securing proper ventilation. If a room is well warmed by a stove, and then several small openings made for the entrance of a good supply of outdoor air, and by a mode that will prevent dangerous draughts, all is right as to pure air. But in this case the feet are always on cold floors, surrounded by the coldest air, while the head is in air of much higher temperature.

The writer believes that ere long the common mode of warming by furnaces will be banished as most pernicious to health, and constant sources of discomfort and economic waste. The reasons for this demand reference to some of the principles of pneumatics.

It has been shown how the air is heated by convection, or changing contact. It is thus the atmosphere is warmed, not by the rays of the sun passing through it, but by contact with the earth and other objects which have been warmed by radiated heat from the sun. The lower stratum of air being thus warmed, becomes lighter, and ascends, giving place to the cooler and heavier air. This process continues, so that the warmest air is always nearest the earth, and grows cooler as height increases.

The air has a strong attraction for water, and always holds a certain quantity as an invisible vapor. The warmer the air the more water it demands, and will draw it from all objects it can reach. When air cools, it deposits its invisible moisture as dew. When the air has all the water it can hold, it is said to be saturated; and when it cools so as to begin to deposit moisture, it is called the dew point.

When air holds all the moisture it can sustain, its moisture is said to be at 100 per cent.; when it holds only one-half as much as its temperature demands, it is said to be at 50 per cent.; and when it holds three-fourths of what its temperature requires, it is at 75 per cent.; and when only one-fourth, it holds 25 per cent.

In summer, outdoor air rarely holds less than half its volume of water; that is, a quart of air usually holds as much as a pint of invisible vapor. In 1838, at Harvard and Yale, at 70° Fahrenheit, the air held 80 per cent, of moisture; at New Orleans it often holds 90 per cent.; at the North, in fogs, the air often holds all it can, or is saturated - that is, holding 100 per cent. Thus it appears that the hotter the air, the more water is demanded by it for invisible vapor, and this it takes from all around.