TRANSACTIONS OF SECTION B. 435 
Recent Progress in Gas-Fire Science, By H. James Yarns, I'.C.S 
M.I.Mech.E. 
Utility being the first motive, the earliest gas fire, being intended to do the 
work of a coal fire, under conditions of greater convenience, was an imitation 
of the coal fire. It either occupied the firespace in the ordinary coal grate, or 
(more frequently) was placed within a similar cavity in a separate stove which 
was set in front of the discarded coal grate. In either case it consisted of a 
series of Bunsen burners, arranged along the front bottom bar, the flames of 
which played or impinged irregularly upon iron frets, wisps of asbestos filaments, 
or, more generally, perforated balls of refractory material which were intended 
to suggest the resemblance of a coal fire; these various refractory bodies were 
heated to low incandescence by immersion in the flames, after the gas had been 
lit for some time. This contrivance, whatever its convenience, resembled its 
prototype, the coal fire, in losing much of its heat up the flue, and in yielding 
only an irregular and inadequate return in the form of radiant heat from the 
fuel consumed. he improper way in which the flame impinged upon the 
refractory material also greatly impaired the completeness of combustion, a 
fact which not only involved waste of fuel, but was liable to occasion an escape 
of harmful combustion-products into the room, especially when the chimney 
draught was poor, or the flue outlet of the gas fire badly constructed. 
The gas-fire idea having been embodied in these early crude forms, it was 
gradually realised that on such a basis gas was no match for coal in point of 
cost, and the question of economising devices came to the front. The manifestly 
great flue losses led to the heat-economising efforts being all directed towards 
delaying the escape of the combustion products until they should have communi- 
cated as large a proportion as possible of their sensible heat to the body of the 
stove, to be afterwards transmitted into the apartment in the form of hot-air 
currents from the stove body. In other words, these early efforts in gas-fire 
economy aimed at concentrating on convected heat. 
A shape which these convection devices usually took was the forming of 
chambers in extended flues within the stove body. The hot combustion products, 
on passing through these chambers or flues, imparted most of their sensible 
heat, by conduction through the walls, to currents of cold air from the room, 
which thus became warmed by passing over the outside of the walls of these 
chambers, and which issued therefrom as hot-air convection currents into the 
room through perforations provided for the purpose. But the heat economy 
thus realised was accompanied by a bad physiological effect, inasmuch as the 
convection currents leaving the stove were so hot that the dew point of the air 
of the apartment was unduly raised, and its degree of saturation lowered; the 
skin and the mucous membranes of the throat and nasal passages of the occu- 
pants offering ready sources of moisture, ‘dry’ sensations, prickling of the 
skin, and other disagreeable symptoms were complained of. Anyone entering a 
room so heated could generally ‘smell the gas fire,’ as it was expressed, partly 
owing to the cause already mentioned, but perhaps more to the escape of 
products of combustion into the room, through faulty construction of the stove, 
and to the burning of dust by contact with the overheated ‘ convecting 
chambers of the stove. Further, owing to the air of the room being hotter than 
the walls, persons sitting near these, while feeling discomfort owing to the 
overheated air, might yet experience chilling sensations owing to radiation from 
their bodies to the cold walls.. These drawbacks engendered a widespread 
prejudice among the public and the medical profession against gas fires. 
It was the personal discomfort which such stoves occasioned to myself that led 
me to take up the matter, and endeavour to devise a new type of gas fire, free 
from these defects, and in so doing I realised that the only way to remove the 
popular prejudice was to remove its cause. First of all it was clear that the 
temperature of the convection currents ought to be reduced, so as to effect a cor- 
responding reduction in the moisture-absorbing capacity of the air of the room. 
It then occurred to me that the old idea of enhaticing the total heating efficiency 
of the fire by increasing the ‘ convected’ heat effect, in the manner described, 
Was a mischievous one, and the source of much of the trouble; and that the true 
remedy must be sought for in increasing the ‘ radiant efficiency ’ of the fire to the 
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