October 2018 Article Featuring




October 2018 Article Featuring




Last month MotometerCentral’s™ MOTOMETER MAKING MEN 2018 article series highlighted inventor, Horace Barnes of Seattle, Washington the partner of this month’s featured motometer inventor, Ary A. Benson, also of Seattle, Washington.


Horace Barnes patented the frame housing for the later commercially marketed Benson “Radio Meter,” “Auto Radio Meter” or National Pyrometroscope Company “Pyrometroscope” for which Ary invented the engine temperature indicating mechanism.  National Pyrometroscope was located in Long Beach, California.  


A Western Machinery magazine article from January 1922 indentifies the “Auto Radio Meter Company of Long Beach, California” as the manufacturers of the “Pyro-metro-scope.” It would seem that the Auto Radio Meter Company might have been a division of National Pyrometroscope tasked with manufacturing their Benson “Radio Meter” or Pyrometroscope, as the article includes numerous photographs of employees –both men and women- milling an, manufacturing and assembling the motometers. 


According to the July 1922 issue of Southwest Builder and Contractor magazine Ary Benson was on the National Pyrometroscope corporate board of directors.


National Pyrometroscope apparently retained a licensed right to market, sell and distribute Ary’s motometer in their name or possibly manufacture all Radio Meters.


Ary Benson belonged to a family of automobile product inventors including Albert O., Guy Mirl Benson and two other gentlemen.  On November 14, 1916, Albert, Ary and Guy combined to invent and patent an “Automobile Speed Signal” device.  That particular device was, essentially, a light panel that illuminated a series of lights as the vehicle past certain predetermined speed rates via different color lens covers.  At the same time Ary, alone, had a “Speed –Indicating Device for Motor Vehicles” gauge patent pending. 


Ary and Horace’s radiator-mounted automobile engine gauge received its patent on November 22, 1921 as a “Temperature Indicator for Radiators.”   That device utilized a temper sensitive/reactive metallic strip that pulled down on a “thermostatic member,” i.e. rod to cause red color celluloid semi-circular panels — they call “Red Wings” — located on either horizontal plane side of the frame housing to form a solid form, complete circle in the middle of the device’s temperature indicating sight window as the coolant temperature heated.


The Benson “Radio Meter” was sold in large “DE LUXE” and “STANDARD” size models.


The Benson “Radio Meter” clearly states its name on the road facing side of he gauge while “Pyro” is stated at the top center of the National Pyrometroscope version. 


Each has temperature range denotations of “AVERAGE” and two sets of arrows on each side to indicate correct engine operating temperature range where the straight edge of the semi-circular panels lead to the center, “DANGER” overheating position (where the two semi-circular halves converge to form a solid circle called the “bulls eye”).  The National Pyrometroscope version has the word/phrase “Pyro” at top center instead of “DANGER” at the overheating position.



The advertised advantages of the “Radio Meter,” Auto Radio Meters” and “Pyrometroscopes” was that their devices – 1) could not freeze, 2) “contains no liquid,” 3) “is not damaged by overheating” and 4) “is operated by “Positive Heat Actuations” obvious knocks against the BOYCE MOTO-METER™ in-specific.


It is not known the number of Benson “Radio Meter,” Auto Radio Meters” or National Pyrometroscope “Pyrometroscopes” were manufactured or sold, however, we know that it was not competitive with the quantity sold by the motometer accessory market leading BOYCE MOTO-METER™ of the Motometer Co. of Long Island City, New York.


Two model sizes were market – the largest, 3 1/4” DE LUXE and the middle size, 3” STANDARD.  They could be purchased in either nickel or 14-carat gold plate finish at a retail cost of $10.00 and $8.50 in nickel plate finish and $15.00 and $12.50 in gold plating, respectively.



Above: Various Benson Radio-meter Ads from 1921 that appeared in trade journals



A "Pyrometroscope Pyrometer (licensed Benson Auto Radio-meter Ad from

Motor West trade journal June 15, 1921, page 12)


Our friend, author Dr. James Cowill in his Automotive Mascots book “Purpose Form & Function Volume One” shows his excellent condition Benson Auto Meter (Above) with and without additional mascot ornament.

Not a lot of these gauge-devices were sold in comparison to the motometer accessory market leading Moto-Meter Company and its BOYCE MOTO-METER™.


Most surviving Benson Auto Radio Meters and National Pyrometroscope Pyrometers failed the test of time due to the choice and quality of temperature indicating panels and the internal temperature sensor material.

Pyrometer - Benson Auto Radio Meter Ad on™
Benson Radio-Meter Ad Motor West on™
Benson Radio-Meter, Motor Land Journal on™
Auto Radio Meter Ad, Motor Land magazine on™
Benson Auto Radio Meter of James Colwill



SINCE 1912

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