bottom and a vacuum gauge on the top. Around the center is a revolving cylinder carrying several different-sized orifices representing the volume of air required for different kinds of cleaning as shown by comparative tests with the tools in actual

use.

Any one of these orifices can be

FIGS. 7 AND 8.-PRESSED STEEL FIOOR TOOLS.

brought into use by turning the cylinder to the proper position.

This instrument makes it easy to apply the orifice test above mentioned to any vacuum cleaning system and avoids trickery in placing the vacuum gauge tube where an induced or untrue vacuum will be shown on the gauge. It also avoids expert manipulation of the tool on the floor, as has often been the case where a certain vacuum was called for at the end of the hose while the sweeping tool was in use.

Trade Literature.

Foxboro Thermometers and Thermographs is the title of an interesting treatise (Bulletin No. 73) profusely illustrated, of the line of indicating and recording thermometers made by the Industrial Instrument Co., Foxboro, Mass. This company has simplified the construction of its apparatus to a notable degree, not only in connection with the instruments themselves

FIG. 9.-RUBBER CLINCHER HOSE

COUPLING.

FIG. 11.-TYPE OF VACOMETER FOR DETERMINING SWEEPING VALUE OF VACUUM CLEANING INSTALLATION.

which are especially designed to add to their ruggedness and freedom from weak parts. The bulletin is supplemented with numerous chart records, which also show the dif

ferent graduations and length of scales. Size 8x11 in. Pp. 40 (punched for binding).

Regulation of Temperature and Humidity is the title of a new and elaborate catalogue just published by the Johnson Service Co., Milwaukee, Wis., which enjoys the distinction of being the largest heat regulation company in the world. The catalogue has a frontispiece of the late Prof. Warren S. Johnson, the inventor of automatic temperature regulation. A concise and readable history is given of this branch of the art, with many illustrations, showing in detail both the features of construction and operation of the various devices making up the Johnson system. The catalogue also covers the company's line of diaphragm valves, reducing valves, pneumatic steam pressure and water level governors, dampers, damper motors, air compressors and pneumatic push buttons and switchboards. Typical installations of heating plants are included, showing the application of the Johnson system under different conditions. A special section of the catalogue is devoted to the company's automatic humidity control apparatus, including its perforated pipe steam humidifier. Photographs of many important buildings are shown equipped with Johnson systems. Size 7x10 in. Pp. 48.

Chamberlin Metal Weather Strip Co., Detroit, Mich., has opened a show room in Indianapolis, at 232 North Delaware street, where a full line of models is on exhibition illustrating the manner in which the Chamberlin weather strips are applied to different kinds and styles of windows and doors.

A STATEMENT.

Statement of the ownership, management, etc., of THE HEATING AND VENTILATING MAGAZINE, published monthly at New York, N. Y., required by the Act of August 24, 1912.

Name of

Post-Office Address. Editor, A. S. Armagnac, 1123 Broadway, New York. Business Manager, Gustave Petersen, 1123 Broadway, New York.

Publisher, Heating and Ventilating Magazine Co., 1123 Broadway, New York.

Owners (if a corporation, give names and address of stockholders holding 1% or more of total amount of stock):

A. S. Armagnac, 1123 Broadway, New York; Gustave Petersen, 1123 Broadway, New York.

Known, bondholders, mortgagees and other security holders, holding 1% or more of total amount of bonds, mortgages, or other securities: None.

(Signed) A. S. ARMAGNAC, Editor. Sworn to and subscribed before me this 31st day of March, 1913. (Seal)

(Signed) A. L. SCANTLEBURY, Notary Public No. 248, Kings County Certificate filed in New York County.

(My commission expires March 31, 1917.)

Leiman Bros.

...

Marsh & Co., Jas. P.

The practical man, applying the rule of thumb and experience, is often heard to say that theory will not agree with practice. The college graduate will put this down to faulty application, quite as likely without being aware that his formula only covers an assumption and may not fit the conditions as they exist. Familiarity with both points of view and the habit of studying cause and effect eventually show the principal factors governing a case. When these are sized up correctly and taken into account, they will prove theory to be the safe and eco12000 B...

a,

nomical way of solving the greatly varying problems.

As a typical failure to recognize the true situation one still meets the belief that a certain amount of fluid requires a certain size of pipe to handle it, under given general conditions. Such a condition, for instance, is the working pressure at the steam boiler. Naturally it is the pressure, or the power behind the fluid, that governs delivery, but, as a matter of fact, a small and most variable portion of the working pressure is expended in creating the movement.

12000 Bt..