ASK YOUR DOCTOR

about the hygienic principles upon which this new System of ventilation is based

In recent years, the science of ventilation has been placed upon a sound physiological basis; hygienists know that effective ventilation is largely a matter of sensible temperature,” consisting of: 1. proper room temperature. 2. Proper relative humidity. 3. Proper atmospheric activity.
To control these factors has been the problem of ventilation engineers, and after many years of study, research and practical exper
iment, positive control has been accomplished. It has come with
the development of the Herman Nelson Her-Nel-Co System of Ventilation.
This system is different from all others. Through its method of operation, it automatically maintains proper indoor atmospheric conditions at all times. Air activity, humidity and temperature are under constant control. Thus, the Herman Nelson System creates a
healthful, invigorating atmosphere throughout the entire room. Pupils and teachers are safeguarded against drafts, overheating and odors.
In contrast with other mechanical systems, but in keeping with the most adv anced hygienic principles, the Her-Nel-Co System does not involve the introduction of a continuous supply of outdoor air into the room. Outdoor air is utilized only when required, and in the quantity necessary, to remove excess body heat.
Leading architects, physicians and heating engineers endorse the principles underlying the Her-Nel-Co System of Ventilation. The fact that this system introduces new economies in building and maintenance costs is an added feature which school authorities appreciate.
Write for the book, The Herman Nelson Her-Nel-Co System of Ventilation.” The Herman Nelson Corporation, Moline, Illinois.
HERMAN NELSON

Her-Nel-Co

SYSTEM OF VENTILATION
Manufactured by the originators and pioneers of Uni vent Ventilation, the Iler-Nel-Co Sys
tem of Ventilation, the Invisible Radiator, and other heating and ventilating innovations that have received world-wide recognition.
Belfast Portland, Me. Boston
Springfield, Mass.
Providence New York City Albany
Syracuse Rochester Buffalo
Scranton Philadelphia Allentown
Harrisburg Erie
Johnstown Pittsburgh Wheeling
Washington Charlotte
Cleveland
Cincinnati Toledo Akron
Louisville Memphis
Chattanooga Knoxville Nashville Miami
Birmingham Indianapolis
Detroit
Milwaukee Appleton Chicago Peoria
Evansville St. Louis
Kansas City Des Moines Minneapolis Duluth
Omaha
Emporia Denver Dallas
Salt Lake City Butte
Spokane Seattle
Portland San Francisco Calgary
Vancouver Winnipeg Toronto London Osaka
Tokyo Oslo
Melbourne Athens
Buenos Aires Shanghai
Pencil Points, published monthly by The Pencil Points Press, Inc., at 258 Atlantic St., Stamford, Conn. Publication office Stamford, Conn. Editorial and Advertising Offices 419 Fourth Avenue, New York, N. Y. Yearly subscription $3.00, single copies 35 cents. Entered as second class matter, March 10, 1930, at the Post Office, Stamford, Conn., under the Act of March 3, 1879. Volume XIII, No. 2.
Dated February, 1932
Minimizes drafts, overheating, and odors