This prosecution related to the same fire, and stood on exactly the same grounds as the preceding. In the course, however, of a trial, which lasted five days, much additional evidence was produced, among which is the following:

Dr Thomas Thomson.-I am Professor of Chemistry in the University of Glasgow. I have directed my attention to the apparatus before me: this was about the beginning of last June. I am acquainted with the ordinary mode of refining sugar. In my opinion, the present plan would be attended with much less danger. The temperature here was about 360: oil boils at 640. There would be no danger if the machine which contained the oil were to leak; if it were a great leak, it would put the fire out; if a small one, it would burn like coals. There was nothing emitted by oil at the temperature of 360 but a little water, which is not the least dangerous. I have tried experiments on whale oil, and I have not been able to satisfy myself that it emits gas at so low a temperature as 640; certainly not lower. It would require a very intense fire to produce that degree of heat. The gas produced from oil will not burn unless it be mixed with six times the quantity of atmospheric air, and not with more than twelve times the quantity. If the whole of the oil used at Severn and Co.'s were to be turned into gas, it would be impossible to

VOL. XIII. PART II.

produce combustion, considering the state of the premises. The use of the oil, as described, for two months would produce no change in it, with respect to the facility of producing gas. When oil is heated to a temperature of 640 degrees, it is changed to an inflammable nature. At 500 it produces a light aqueous vapour, which, carrying some oil with it, might burn, but, at that temperature, it could not ascend above an inch or two, if it ascended at all. It is impossible that at 360 degrees any vapour could pass at the mouth of the leaden tube, which is 16 feet from the vessel. No inflammable vapour, even at the heat of 600, could pass from the oil vessel through the tube. It would become oil, and fall down again before it reached near that height. He spoke of whale-oil, and the oil of cod. He tried them both. He tried the action of heat at 360, for six weeks, on oil, and the only change was, that the colour was darker, and, when cold, it was thicker; but it was not rendered more inflammable. Oil, at a temperature of 640, below which it will not produce gas, emits a smell the most offensive in existence. I have been knocked down by it. I know what is called dipples-oil. An application of heat at 360, for two months, would certainly not produce dipple-oil. I have passed whale-oil through a red-hot iron tube three times successively, without producing dipples-oil. Dipples-oil is very inflammable, and boils at 180 degrees. I failed to produce dipples-oil with my own apparatus. It is impossible for such a vessel as was used by Severn and Co. to produce dipples-oil. No change could take place in the oil at the heat of 350 deg. for two months, except its becoming blacker and thicker. At 440 deg. it would not produce any change such as he before mentioned. There is a substance which is found in whale-oil, which, by great pains and

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care, may be separated from it, and this, at a red heat, would produce a gas; but this would not burn. I think it is impossible that any danger could occur in this vessel if there were a fire twenty miles long under it. It never could be heated beyond 640 deg. in an open vessel. If the vessel were shut, it might be heated more, but it would burst. In the oil vessel used by Severn and Co. it was impossible the oil could have gone into the pipe and got out. At 450 deg. oil increases about a fifth of its bulk; but as there were twothirds of the room vacant in this vessel, it was impossible the oil could have been raised into the pipe. At the temperature of 340 oil gives out an aqueous matter a steam which condenses at the top of the vessel. From thence it falls back into the oil; and as the water is heavier than the oil, it sinks; in its way down it is expanded again by the heat, and makes a crackling noise as if the oil were boiling. There is, however, no danger in this. If it were put to me as a problem, I do not think I could set the place on fire by this, unless the machinery was altered. Sugar is very inflammable. It will burn when it boils over. It would then burn as it ran on the floor. I look upon sugar as the most combustible substance next to gunpowder. Pure sugar boils at 250 deg. At a few degrees higher-I believe not more than ten it begins to emit an inflammable gas, like that from oil, but the difference is, they are produced at different temperatures. The flame of sugar, if the place were close, would be red; if in the open air, it would probably be white.

Dr Davy, a member of the Royal Society, and a brother of Sir Humphrey Davy.-Heard Dr Thomson examíned: never made any experiments himself on this oil, but saw some made, on Saturday, at Messrs Severn's. At a heat of 350 or 360, a lighted paper,

introduced into the vessel, was ex tinguished. The vessel was as large as the original one. There were about three inches of oil in it. The other answers of this gentleman concurred, as far as his personal knowledge of the facts extended, with the answers given by Dr Thomson.

Cross-examined by Mr SCARLETT.— His knowledge as to oil, in this case, was confined to what he saw on Saturday last. He had not made any experiments himself, as to oil. He had for some time given great attention to chemical subjects in general.

William Thos. Brande.-Is Profes sor of Chemistry, and Lecturer to the Royal Society. He made several experiments, with respect to this case, before and since he was first examined. He got a copper basin of sugar and one of oil, and placed them on a fire, When the heat of the sugar was 400 degrees, he put a lighted paper to it, and it took fire; but the paper was quenched when put into the oil. He had made the experiment with the be lief that the oil would take fire first. This was before he was last examined. The oil was 600 deg. when the thermometer was taken out. He then put a lighted taper to it, and a blue lambent flame played for a while on the top, and went out. This was in the daytime. What appeared to him to burn was an inflammable vapour. He did not consider that the same effect would be produced by putting the ta per to a pipe at the bottom of the vessel. He tried experiments on new and old oil. He took some oil which for 29 days had been exposed to heat of from 400 to 500 degrees; and having again heated it in a bolt-head, or bottle with a long neck, he applied a lighted taper to the tube from it, but found no vapour or gas. He observed that an aqueous vapour was formed, which condensed in the neck of the bottle, and, falling down into the oil,

occasioned a crackling noise, as if the oil were boiling. This vapour was not inflammable. He agreed with Dr Thomson as to the crackling noise, and the cause of it. He once thought that oil boiled at 220 degrees, but he afterwards found that it was the water escaping and falling again. Another experiment was made with oil exposed to a heat of about 400 deg. for 29 days. When it reached 560 deg. a vapour was seen to arise. At 575 a vapour came off, consisting of aqueous matter and oil. At 610 deg. vapour came, which burnt, accompanied with gas, which, being carbonic, did not burn, but extinguished flame. The vapour, at 575 degrees, flashed a little, but he could not say whether it burnt continuously. The last oil was heated in a digester. This experiment was made in June last. As to new oil, he never got any vapour or gas at any temperature below 600 deg. In old oil, in an open vessel, some inflammable vapour was obtained at 550, but no gas. The vapour was not continuously inflammable. The tube from which the vapour came in the second experiment (in June last) was only six inches long. Mr Brande fully concurred in the opinion of Dr Thomson, as to the new mode of refining sugar being much less dangerous than the common. There was much less danger in oil heated to a high temperature than sugar to the same temperature. There would be no danger from oil at 450 or 500 degrees, but from sugar, at such temperatures, there would be imminent danger. On the whole, as far as his experience went, he considered the plan decidedly superior.

Cross-examined.-He conceived that if vapour rose up into the pipe, it would fall down again. That would certainly depend on the temperature of the pipe. The pipe would of course become warmer each time the vapour went up; and if the tem

perature of the pipe became greater than that at which the vapour was condensed, the vapour would escape. The pipe must be, he should consider, above 500 degrees of heat before the vapour could escape. He could conceive a case where the creation of vapour below was more rapid than its condensation above; and the effect, in time, would be that some of it should escape, and perhaps at a somewhat lower temperature.

Re-examined. He could conceive that from a vessel of water the steam might escape at the end of the tube, at a heat of 212 degrees. This could not be the case with oil, unless it were elevated to between 600 and 700 deg.; it would then be in the same predicament as water in a vessel at 212 deg. If the melting point of lead was 612, it would melt before this effect could be produced.

Mr Parke examined by the SOLICITOR-GENERAL.-Witness had all his life applied himself to the study of chemistry. He had examined the ap paratus, a model of which was now exhibited, for the purpose of giving evidence on the last trial; and he had made many experiments, in order to ascertain the inflammable qualities of oil. In his judgment the new mode of communicating heat to sugar was less dangerous than the old. He apprehended that it was absolutely impossible that danger could arise to the building from the new apparatus.

Michael Ferriday.-Had for a considerable time been engaged in the study of chemistry, and had assisted at some of the experiments of Sir H. Davy. Mr Wilson's plan was well understood by him, and he certainly considered it to be much more dangerous than the ordinary method of refining sugar. During the last two years he had himself, and in company. with other gentlemen, made various experiments on heated oil. The first

was made on a quantity of 24 gallons, put into a copper 15 feet by 14, and after it had been heated upwards of 20 days. The boiler was of a circular shape, and the top of it therefore convex. A thermometer was put in nearly at the bottom, and another towards the top of the boiler. It had also a hood and a tube, or vent-pipe. He soon perceived that oil became inflammable in a very different degree after it had been once subjected to the action of fire. By repeated distillation it acquired properties altogether new : it produced a matter which was called aptha, and became a volatile instead of a fixed subject. His meaning was, that it arose into vapour much sooner, and he had procured oil which would rise into vapour at the ordinary temperature of the atmosphere, and which would burst into flame on the application of a lighted taper. This was call ed explosion in chemistry; but it took place without noise, or, at least, detonation. His first experiment had for its object to discover whether oil would yield these inflammable gases at the heat of 360 degrees, and after having been previously heated 22 several times. In a glass retort, he found it would give out such vapours at that point; and when tried on the larger scale in a boiler, it did so at the degree of 410. It arrived at this degree of heat in about ten minutes. He collected the vapours in a pan, and a light caused the atmosphere in it to burn. In 20 minutes, and at the deg. of 460, the oil boiled over. The vapours as cended in jets and spirits, through a pipe two feet high, and placed above the apparatus. In the boiling state, a thick scum formed on the surface, as on boiling milk, and would run over in time, as in the instance to which he alluded, when it flowed over in the fire-place, and they were obliged to throw water on it. This took place in Whitecross-street, and when Mr Tay

lor and Mr Wilkinson were present. After the fire was put out, the ebullition continued for a considerable time. He tried a small quantity of the same oil at home-it emitted vapour at 410 degrees, and at 480 degrees exploded with a brilliant combustion. The first experiment was made in the month of February, and two subsequent ones were made in the following April. At the first a steam-bin was filled with vapour in 16 seconds, and ultimately took fire; a barrel also was inverted over the apparatus, and its sides were scorched, although the flame went out. [This barrel was afterwards produced in Court; it had been taken, at the time of the experiment, in rather a wet state, from an adjoining yard.] He had not examined the oil farther than to ascertain that it contained no sulphu ric acid. On the next experiment the vapour ignited at the degree of 486. He had also examined the effect of fire on sugar, which he found to become quite another substance when so decomposed. With white sugar, however, it required a heat of 430 degrees, in a metallic pan, to alter it. This might be accomplished, with coarse moist sugar, at a heat of 230, but he had not ascertained whether it was inflammable. He felt perfectly confident that oil, used as it was in the process of the plaintiffs, would be rendered volatile, and liable to be very rapidly heated. It would remain in a state of ebullition for two hours sometimes, after the fire was withdrawn. The witness, after describing several further experiments, producing similar results, declared his opinion, founded on these reasons, that the process in question was dangerous, both in a high and a low state of the atmosphere.

Mr Bostock is Chemical Lecturer in Guy's Hospital. He was of opinion that, by the introduction of the new plan of refining sugar, a degree of danger was incurred, which was in no de

gree counterbalanced by the danger it removed. He had not given very much attention to this particular subject himself, but, from all he saw, this was his opinion. From all he saw since the last trial, his opinion of the danger of the new process was very much strengthened. The greatest degree of danger arose from the difficulty of restraining the temperature of oil at a certain height, the same degree of heat being applied, and also by the change which oil experiences, by being kept for a long period at a temperature of 360. Prepared oil (oil used in this way) acquired a property of giving out vapour at a lower temperature than new oil would do. Another cause of danger was the uncertainty of the effects. We really, he thought, were not sufficiently masters of the subject to use oil as an agent in this way. He was asked his opinion of this apparatus before he saw it, and he gave itthat it was dangerous, for the reasons he now mentioned. It was dangerous so to use oil in a sugar-house, without having made previous experiments on it. At first he was not aware that oil long exposed to the action of heat would emit inflammable vapour at so low a temperature; but before he knew this, he gave the opinion men tioned, on the generally received opinion that oil would emit a gas at a temperature of 600. He also thought that danger arose from the very great difficulty of checking the heat beyond a certain degree by any means independently of the constant attention of the workmen. Another cause of danger was the risk of the vessel leaking, and the oil dropping into the fire, and acting as fuel; and, as connected with this, the danger of the oil in the vessel becoming reduced by such means, so as to become heated suddenly, the same fire being continued under it. Another circumstance which produced some danger, was the difference of tem

perature in different parts of the vessel. He thought that after the oil had been for some time kept at 360, any accession of heat would be dangerous. In the hands of such persons as usually attended furnaces, all those dangers would be increased, because they would not be on their guard. Witness had listened to Mr Ferriday; had attended some of his experiments: he took notes at the same time, and concurred with him in his deductions from them. He did not measure the heat of the fires used on those occasions. It was difficult to measure the heat of fires exactly. He could not doubt but that the quality of oil was changed by being exposed for a length of time to 360 degrees of heat. This change consisted in its being capable of emitting vapour at a lower temperature than common fresh oil. This would depend on the rapid accession of heat. He saw the experiments at Messrs Severn's, by Mr Parkes and others, on the 9th of December; he took notes of them when he went home. He was informed that the oil he saw used had been exposed to a heat of 360 degrees for 35 days; but that it had been discontinued for some time, and renewed within the last four days. He arrived at half-past 12, and, on the premises, was told that the fire had been lit under the boiler at 9. The boiler was a fac simile of the one used in the new apparatus. The fire was moderate, and the thermometer stood at 360 degrees. It was opened at top, and a lighted taper put in; but no vapour was perceptible. Fuel was then added, and in 25 minutes the temperature was raised to 376. The vapour did not light even then. There was then a mixture made of the vapour which the vessel contained, with the common air, but there was no combustion. He then saw the old boiler, but it did not appear rent or burst. The experiments he saw were not contradictory to those