APRIL 22, 1897 | 
NATURE 
597 
wants to know how nitrate of soda, sulphate of ammonia, and 
shoddy, compare in his own land and climate, the only way of 
ascertaining the fact is by field experiments repeated through 
many years, till the influence of an average season is ascertained. 
1S NE 
COLLIERY EXPLOSIONS AND COAL-DUST. 
At a meeting of the Physical and Chemical Section of the 
Bristol Naturalist Society, on January 26, a paper was 
read, by Mr. Donald M. D. Stuart, upon ‘‘ The Chemistry of 
Colliery Explosions due to Gases derived from Coal-dust,” in 
which the researches of Faraday, Verpilleux, Vital, Marreco, 
Mallard, Le Chatelier, and others were given, and attention was 
drawn to the points they emphasised. Faraday observed in his 
report upon the Haswell Colliery explosion: ‘* There is every 
reason to believe that much coal-gas was made from the coal- 
dust in the very air itself, by the flame of the fire-damp;... 
and that much of the carbon in this dust remained unburnt 
only for want of oxygen.” M. Vital concluded that—‘* Very 
fine coal-dust rich in inflammable constituents, will take fire 
when raised by an explosion, and that portions are successfully 
decomposed, yielding explosive mixtures with air, whereby the 
fire is carried along.” Marreco remarked—‘‘ The coal-dust is 
in part submitted to destructive distillation” ; and Mallard and 
Le Chatelier found that gaseous matters were evolved from the 
coal-dust by the action of the fire-damp explosion. Mr. Stuart 
observed. These physicists and chemists found that the coal- 
dust did undergo dry distillation while in atmospheric suspension 
in a mine passage, after the originating explosion; and the 
educts added to the explosive effects. He had carefully observed 
the effects of explosions not only at the point of origin, but 
throughout the field of the disturbances, and found Faraday’s 
hypothesis of the dry distillation of coal-dust essential to 
account for the phenomena observed through thousands of 
yards of mine passages. He observed that the disruptive 
effects of an explosion of methane and air were necessarily 
limited to the immediate vicinity of the explosive mixture ; but 
the disruptions beyond and to remote distances required an 
explosive agent coextensive in distribution, and this agent was 
coal-dust. 
The fields of disturbance exhibited the effects of gas-explosion 
at separate points of space, with intervals of no explosion but 
of heat, partial combustion, and dissociation ; requiring, for 
explanation, a chain of chemical changes liberating quantities 
of heat, and accumulating an explosive mixture at the place of 
explosion. The question arose whether a given volume of air 
could hold in suspension, as dust, a sufficient weight of coal to 
give, by its resolution into gas, more gas than the given volume 
of air was capable of burning or exploding ; and investigation 
showed that the coal yielded a quantity of combustible gases, 
not less than one half the volume of the air in which it was 
suspended. In these conditions there could be only partial 
combustion, until a place was reached where the mine passage 
emerged into a capacious chamber in which the unconsumed 
gas found sufficient atmospheric oxygen, and was exploded by 
the flame in the partial combustion referred to. The disruptive 
effects were located in places of large air capacity in the paths 
of coal-dust. 
At the point of origin, the coal-dust was reduced to coke, 
the residue of dry distillation ; and this phenomenon was of 
frequent recurrence in the paths of the propagated explosions. 
Amorphous carbon was found universally deposited in the field 
of explosions, chiefly upon the vertical side-walls ; it was also 
in copious suspension in the stagnant atmosphere in the pas- 
sages, and the effluent gases at the shafts. Combustible bodies, 
as timber, cotton fabrics, and candles, forming obstructions in 
the paths ‘of coal-dust and between the explosions, were not 
consumed or burned. The bodies of the victims in these in- 
tervals were blistered to various degrees ; the cotton fabrics re- 
tained their external form, but had been deprived of their volatile 
matter, the candles had melted and run together, and the 
adjacent coal-dust and lumps of coal had undergone dry dis- 
tillation. These effects upon the coal, men, calico, and candles 
disclose the fact that the atmospheric oxygen in the mine 
passages was not more than adequate to supply a portion of the 
educts of the coal undergoing distillation ; consequently there 
was no oxygen available for the chemical requirements of other 
combustible bodies, as timber, clothes, -cotton fabrics, and 
candles. 
NO. 1434, VOL. 55 
The chemical changes in the intervals from explosion to ex- 
plosion caused considerable diminution in the atmospheric 
pressure, indicating a very small production of permanent gases, 
and the employment of the atmospheric oxygen to form readily 
condensible gas. 
The explosions at the non-gaseous Camerton and Timsbury 
Collieries were originated by the heat in the products of the 
exploded blasting powder. The temperature of fired powder 
of a similar composition was determined by Abel and Noble at 
1800" to 2000° C. ; the products, therefore, struck the coal-dust 
in the immediate vicinity while at an exalted temperature, 
certainly higher than that of the gas retort, which is below 
1000° C. The educts of the coal-dust would consequently be 
similar to ordinary illuminating gas. The composition of London 
gas is given (by Frankland) at 51°24 per cent. free hydrogen, 
38°84 per cent. gaseous hydrocarbons, and some other bodies. 
Upon the foregoing and other data, Mr. Stuart advanced the 
following rationale of a colliery explosion :—The educts of the 
coal are in excess of the relative combination volumes of atmo- 
spheric oxygen present; therefore the large proportion of 
_ nascent free hydrogen present, seizes the principal part of the 
oxygen, liberating heatin the combination. Some of the hydro- 
carbons obtain the remaining oxygen, causing a limited com- 
bustion, as in the preparation of diamond black, disengaging 
more heat, and placing amorphous carbon in suspension. At 
the temperature of burning hydrogen, the hydrocarbons that 
have not undergone change, for want of oxygen, are dissociated, 
placing more amorphous carbon in suspension, and yielding free 
hydrogen for disruptive effects. 
_ The heat in the products of the exploded powder, therefore, 
instituted a series of chemical actions in the coal-dust, in which 
large quantities of heat were disengaged, and free hydrogen 
placed at disposal for disruptive action. This series is regener- 
ative by virtue of the heat liberated, which instituted a similar 
series in the adjacent coal-dust ; and these activities are of con- 
stant and similar reproduction along the paths of coal-dust until 
a place is reached, which supplies a large quantity of atmo- 
spheric oxygen, in which the accumulated hydrogen diffuses, 
and the mixture is ignited by the flame in the partial combustion, 
causing an explosion. This explosion liberates more heat, and 
re-establishes a similar chain of chemical changes in the coal- 
dust beyond, closing in a second explosion at the next abnormal 
supply of air, and propagation proceeds along each path of coal- 
dust so long as adequate oxygen is available, and wet surfaces 
do not intervene to reduce the temperature below the point at 
which the coal undergoing distillation yields sufficient free 
hydrogen to supply by its oxidation enough heat to make the 
actions continuous. The paper was illustrated with limelight 
slides, and was followed by an interesting discussion. Upon 
the motion of the President, Mr. Stuart was cordially thanked 
for his paper. 
A NEW DIPHTHERIA ANTITOXIN. 
RECENT number of the Archives des Sciences Biologiques, 
issued by the Imperial Institute of Experimental Medicine 
in St. Petersburg, contains a highly important communication 
from Dr. Smirnow, on a new method of obtaining a diphtheria 
antitoxin of great therapeutic value. For the last three years 
Dr. Smirnow has been working on this subject, and the present 
memoir places experiments, which before were only in a tenta- 
tive stage, on what now appears to be a sound and practical 
basis. 
As is well known, the preparation of curative diphtheria 
serum involves not only great expense, but also a great deal of 
time ; the raising of a horse’s serum to the requisite pitch of 
immunising properties requiring many weeks. Dr. Smirnow 
has been endeavouring to produce an antitoxin, the preparation 
of which is less costly and less cumbersome. The method 
adopted was that: of electrolysis, and in the first instance 
ordinary serum was electrolysed ; but as this led to nothing, 
virulent diphtheria broth cultures were substituted for serum, 
and the results obtained were highly encouraging. These 
electrolysed cultures were found to contain an antitoxin of great 
efficacy, and, even when employed in smaller quantities than the 
therapeutic serum, it entirely protected animals from the effects 
of diphtheria poison. ‘‘ Le traitement par cette antitoxine 
marche d’une maniére remarquablement satisfaisante: malgré 
les périodes les plus avancées de la maladie, il sufft d’un demi 
