which is drawn the warm air, thus aiding the evaporation. Capillary attraction draws water up through the wicks. The wicks are wet

BUDDINGTON HUMIDIFIER INSTALLED ON RADIATOR.

on the wings as long as there is water in the container. The device is listed at $3.00.

TWENTY-EIGHT YEARS OF STEEL (NATIONAL) PIPE PROGRESS is presented graphically in a bulletin just published by the National Tube Co., Pittsburgh, Pa. A series of illustrations is included, showing similar progress in other lines of manufacture and thus indicating the tremendous advances in every line, but in none is the advance more spectacular than in the manufacture of steel pipe. Steel pipe was first made in 1887, the tonnage for that year being 300 tons. To-day, it is pointed out, steel pipe represents almost 90% of the total tonnage of screw-joint pipe made in this country, a substantial portion of which is "National" pipe. The full story of the rise of steel pipe, it is announced, is contained in "National" Bulletin No. 24, a copy of which may be had by addressing the National Tube Company.

COCHRANE HEATERS FOR STEAM POWER PLANTS, as used in heating, metering and softening water for boiler-feed and other purposes, are treated at length in a new publication (Catalogue No. 710), recently issued by the Harrison Safety Boiler Works, 3189 North 17th St., Philadelphia, Pa. The booklet is devoted especially to the uses of open heaters for the purposes stated. The amount of fuel that can be saved by the use of exhaust steam is first explained and a convenient diagram is given by which the percentages of fuel saving in any given case can be easily ascertained. The essential parts of an open feed-water heater are then considered. after which there are chapters on heating boiler feed in condensing steam power plants, including various arrangements to be used where the exhaust steam is excessive or deficient, the effects of open heaters in .connection with exhaust steam heating and drying systems, the heating of water for purposes other than boiler

feed, such as hot water heating, etc. Finally there is a detailed comparison of the open heater, as represented by the Cochrane feed-water heater, with the closed or pressure type of heater, concluding with suggestions for the specification of an open feed-water heater. Size 6 x 9 in. (standard). Pp. 100.

COMINS ELECTRIC PSYCHROMETER, for determining the humidity of the atmosphere, made by the American Moistening Co., Boston, Mass., is described and illustrated in its latest form in a new circular issued by the manufacturers. One of the important advantages mentioned in connection with this instrument is that if it can be used in crowded spaces among machinery

hygrometer. In both cases the wick for the wet bulb must be kept in proper condition. The circular contains some suggestions for the care and preparation of the wet-bulb thermometer and there are also included some handy psychrometric tables. Size 31⁄2 x 6 in. Pp. 16.

SIMS STEAM-TUBE STORAGE HEATERS, for laundries, hotels, hospitals, and apartment buildings is the title of the latest bulletin (L-4) issued by the Sims Co., Erie, Pa. Special attention is paid to installations requiring large quantities of hot water, with live or exhaust steam the heating

as

medium. The catalogue is notable for the omission of all superfluous matter, no argument being presented to convince the reader of the quality of the Sims products. It is stated, however, that all work is guaranteed. The catalogue gives the general specifications for this type of heater, which is known as the Sims B-H heater, and these are followed by a series of 18 tables covering a sufficiently wide range of sizes and capacities to meet closely any combination that may be called for. Full directions are given for using the tables, by which answers may be obtained to problems like the following: To heat 250 gal. per hour from 50° to 180° F., with steam at atmosphere, providing storage for 150 gal. Another example which may be answered by the tables is the following. To heat 5,000 gal. per hour from 50° to 180° F., with steam at 50 lbs. pressure, storage 1,500 gal. The concluding pages are devoted to illustrations, with tables of connections, of the Sims B-H heater of different types. Size 6 x 9 in. (standard). Pp. 32.

METAPHRAM DAMPER REGULATORS, for high pressure, low pressure, hot water and vapor, embracing the complete line of these devices, are presented in new circular matter issued by the National Regulator Co., Chicago, Ill.

The line embraces five types: Type H-P 7-in. for high pressure; Type A-Jr. 4-in., for low pressure; Type A 4-in., also for low pressure; Type B-C 7-in., for low pressure or vapor; and Type D 10-in., for vapor. These regulators are all metal, dust proof, and sensitive. They are guaranteed for the life of the boiler. The universal adjustment feature makes them applicable for pressure or vapor by changing the fulcrum position and shifting the weights and lever. They are made to fit any style of low pressure boiler and to work on ounces from 0 to 15 lbs. pressure, and on hot water at 5° change in temperature. The high pressure type is designed to operate on boiler pressures from 15 to 175 lbs.

Cooperstown, N. Y.

1123 Broadway, New York

Chimneys are one of the oldest and most useful inventions conceived by man. They are of greater and more fundamental importance than anything that any modern inventor has contrived. In a primitive form they are almost as old as the human race, for a fire could not be made to burn with any regularity, nor the smoke kept from being a nuisance, without a draft. The first chimneys were probably natural crevices in the rocks forming the walls and roofs of caverns which were used for human habitation at that period.

Later stones were piled together to form rude chimneys somewhat as a camper piles them to-day to cook his food. Indian wigwams were commonly turned into very smoky and ineffective chimneys during cold weather by making an opening at the apex of the tent and lighting a fire on the ground in the center.

It takes engineering ability to make a good chimney, and one must understand the laws of Nature which apply to their construction and operation. Modern factory chimneys are triumphs of scientific construction, being built tall in order to maintain a large, hot fire, and the heated air and gases pour up through some of them with the velocity of a small hurricane at the rate of thirty-five to forty miles an hour.

Each one of us is directly affected by the sizes of the chimneys used in the world to-day, many of the trials and tribulations of our journey through this vale of tears being directly traceable to them. This, however, is not so much the fault of the chimneys as it is of the persons who build them and either deliberately transgress Natures laws or are largely ignorant of them.

MOST COM MON ERROR IN CHIMNEY WORK.

The most common error made in regard to chimneys is that of not distinguishing between the size (which governs the volume of smoke they can handle) and the height (which determines the intensity of the draft). A chimney may be high enough yet with an area too small to do the work required. On the other hand it may be large enough but too low to produce a draft of the strength required to pull the air through the fire and up the chimney at a sufficiently rapid rate. Either fault, or a combination of both, will result in unsatisfactory service and will require remedying.

BASIC PRINCIPLE INVOLVED.

The easiest way to understand the

operation of a chimney is to consider the great laws of Nature governing its operation for there is, indeed, nothing so very mysterious about the process. The same force which supports the toy balloon and operates the hot air furnace causes the draft in the chimney. This is the simple fact that heated air expands and occupies a greater volume than the other air of a lesser temperature. Therefore, if a cubic foot of air outside the chimney weighs 0.07 lbs. and a cubic foot of the chimney gases at their higher temperature weighs only 0.04 pounds then every vertical foot of air in the chimney means an unbalanced pressure of 0.07 0.04 or 0.03 lbs. per square foot at the base. This unbalanced pressure has a tendency to equalize by the rising of the lighter gases, but, since their place is taken by more heated gases coming directly from the fire, the temperature, of course, never does equalize and the action continues its operation as long as the fire is kept burning.

From this basic principle all chimney action is governed and many chimney failings can be explained. For instance. -the draft of a chimney is never as good in summer as in winter-because the outside air is colder in winter, the expansion of the chimney gases at the same temperature is therefore relatively greater and the intensity of the chimney draft is consequently increased.

It is a well-known trouble with chimneys that when out of use for any considerable period trouble is likely to be experienced in "starting the draft." This is easily explained by the fact that, in starting, the cold chimney will cool off the gases to a point where their temperature may be the same, or nearly the same, as the outside air, thus causing them to contract and lose their buoyancy. This, of course, immediately results in killing the draft, as the draft depends absolutely on a temperature difference. and the expansion resulting therefrom.

Ordinary residence chimneys have little trouble on account of height owing to the fact that most residence heating systems burn large size anthricite coal which makes a very hot clear fire and offers little resistance to the passage of air through the fire bed. In fact, many of the older railroad stations and simi

lar places use coal stoves with only a stove pipe extended through the roof, this pipe seldom being over 10 ft. in height. But an attempt to burn smaller sizes such as pea and buckwheat would be doomed to failure under such conditions.

The ordinary residence usually employs a chimney between 25 and 60 ft. high, the area being proportional to the size of the house and it is interesting to note that it is possible to burn No. 1 buckwheat coal with a chimney 55 ft. high if the fire bed is not made too thick. Down-draft boilers should have chimneys at least 60 ft. high to operate successfully.

Chimneys have to overcome their own losses, these losses consisting of the friction of the gases rubbing against the sides in their upward passage. For this reason a circular-shaped flue is most desirable, there being less surface exposed in comparison to the area than in any other shape. Most high stacks where the friction builds up to a considerable amount are, therefore, made round in cross section.

The next most advantageous shape is square and the next, after that, is oblong with the long side not more than double the length of the short side. In flues where it is necessary to exceed this proportion two separate flues of more desirable shape can sometimes be used with advantage.

With the same idea of reducing the friction of the gases on the sides it is most desirable to build a chimney flue straight from top to bottom as all changes in direction, or even in shape, produce an additional friction loss, as does also the condition of the interior surface. The smoother the surface the less the rubbing effect and for this reason the use of flue tile is advocated, this being tile flue pipe made in various forms and shapes and with a very smooth interior surface. Fig. 1 shows a plain brick chimney without tile and Fig. 2 the construction of a chimney using flue tile.

From the above it can be seen that the most efficient chimney, as far as draft is concerned, is one built perfectly straight from the bottom up, round (or

8"Brick

FIG. I-PLAIN BRICK CHIMNEY WITHOUT TILE.

nearly round) in the shape of the interior flue, and lined with tile, or with the interior surface made as smooth as possible by other means. There is no advantage in tapering the inside of a chimney to a smaller size toward the top as this retards the flow of the gases.

Having a chimney built upon desirable lines, as far as draft is concerned, it may, of course, still be too small, and in this

FIG. 2-CHIMNEY WITH FLUE TILE.

When flue tile is used the interior dimensions are not in even figures, the exact dimensions of commercial sizes being given in Table II.

When square or rectangular chimneys are designed for fire-places which burn wood or bituminous coal they are usually made with an area of 10% to 12% of the fire-place opening, while with round flues the area may be reduced to 8%. For anthracite coal the rectangular or square flue may be reduced to 8% and the round flue to 6%. Ordinary stoves are readily served with an 8 in. x 8 in. flue provided no other connections are made to it.

All chimney walls should be 8 in. thick to avoid danger of fire from sparks working through the joints and the building laws in some cases demand not only 8 in. thick walls but tile linings as well.