THE ROYAL ARTILLERY INSTITUTION. 
227 
IGNITION OF COTTON BY SATURATION WITH FATTY OILS. 
By John Galletly. 
Head at Brighton Meeting of the British Association, August, 1872. 
The following experiments have been made with the view of giving greater 
precision to our knowledge of the kindling of cotton or other open combustible 
materials which happen to have imbibed animal or vegetable fatty oils. Graham* 
mentions “ that instances could be given of olive oil igniting upon sawdust; of 
greasy rag9 from butter, heaped together, taking fire within a period of twenty- 
four hours.” The danger of fire from this cause is familiar to those manufacturers 
who coat any textile fabrics with varnishes containing drying oils, and also to 
turkey red dyers, from the olive oil employed in their process. Generally, it 
is stated in “Watts’ Dictionary”! that this combustion “may take place in 
intervals varying from a few hours to several weeks, when considerable masses 
of lamp black, tow, linen, paper, cotton, calico, woollen stuffs, ships’ cables, 
wood ashes, ochre, &c, are slightly soaked in oil and packed in such a manner that 
the air has moderate access to them.” Nevertheless there is great vagueness 
about the exact conditions in which actual ignition of the mass would take place, 
what size of a heap might be necessary, and the various powers of different oils to 
produce this result. Graham states, in the report already quoted, that the ignition 
of heaps of the materials under discussion “ has been often observed to be greatly 
favoured by a slight warmth, such as the heat of the sun.” This is a very im¬ 
portant observation. I shall only, however, mention in the meantime that the first 
of my experiments were made at a temperature of about 170° Fahr., but I have 
some made at a heat a little over 130°, or about the temperature a body acquires 
by lying perpendicular to the sun’s rays; the former temperature might represent 
the heat attained in the neighbourhood of a steam-pipe, a heated flue, or in front 
of an open fire. For completeness I shall repeat in this paper, along with later 
results, some observations published a few weeks ago in the “ Oil Journal.” 
JBoHed Linseed Oil , with Chamber kept about 170° Fahr .—A handful of cotton- 
waste, after being soaked in boiled linseed oil, and removing the excess of this by 
wringing, was placed amongst dry waste in a box 17 ins. long by 7 ins. square in 
the ends. Through a hole in the cover of this box a thermometer was passed with 
its bulb resting amongst the oily cotton. Shortly after reaching the temperature of 
the warm chamber, the mercury began to rise rapidly—viz. from 5° to 10° every 
few minutes, and in 75 minutes from the time the box was placed in the chamber, 
the heat indicated was 350° Fahr. At this point, smoke issuing from the box 
revealed that the cotton was now in a state of active combustion, and, on removing 
it to the free access of air, it burst into flame. In another similar experiment the 
temperature rose more slowly, but reached 280° Fahr. in 105 minutes, when, from 
the appearance of smoke, it was plain that the cotton was burning, and the whole 
mass was soon in a flame on being placed in a current of air. On a smaller scale, 
1 tried a quantity of the oiled cotton that just filled a common lucifer match box; 
within an hour it was on fire, the temperature of the chamber being 166° Fahr. 
Raw Linseed Oil, as generally supposed, does not so readily set fire to cotton as 
the boiled oil, but in two experiments where the size of the box employed was 
6J ins. long by 4-g ins. square in the ends, active combustion was going on, in the 
one case in five, in the other in four hours. 
* Report on the burning of the steamer ‘‘'Amazon.” See Chemical Soc. Quart. Journal, 
Vol. Y. p. 34, 
f Yol. II. p. 880, 
