SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 8l 



In 1920 the Smithsonian Astrophysical Observatory designed and 

 built a new instrument for the measurement of radiation called the 

 " melikeron." It is essentially different from the ordinary type of 

 radiation instrument such as the pyranometer, pyrgeometer, bolome- 

 ter, etc., in that radiation is absorbed not upon a flat surface but by 

 a device shaped like a honeycomb. This makes the melikeron, by vir- 

 tue of its form, approximately a " black body," capable of absorbing 

 practically all radiation falling upon it. A detailed description of the 

 instrument and tests made upon it are given in Smithsonian Miscel- 



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Fig. I. — Melikeron and mounting, showing special water-circulating vesti- 

 bule and water-circulating, " pin-cushion " shutter. 



W — Wooden insulator. 

 M — Melikeron. 

 5^— Shutter. 

 H — Honeycomb absorber. 



D — Metal diaphragms. 

 C— Circulating water. 

 F — Blackened metal points. 



laneous Collections, Vol. '/2, No. 13. Being well adapted to the mea- 

 surement of long wave radiation such as is emitted by bodies at low- 

 temperature, Melikeron No. i was chosen by Dr. Abbot for his mea- 

 surements on the radiation from a nude subject in Dr. Benedict's 

 laboratory. A special mounting was made, with the melikeron en- 

 closed in a wooden case to keep air currents away. The front was 

 provided with a diaphragmed vestibule through which water circu- 



