Sentence:  To reduce heat transfer from the <WSD>hot</WSD> gas to this anode holder outside the region of the arc , a carbon shield was attached to the surface providing an air gap of 1/16 inch between the plate and the surface of the anode holder . 
Meaning of the word marked with <WSD> tags:  used of physical heat; having a high or higher than desirable temperature or giving off heat or feeling or causing a sensation of heat or burning