depend, as well as the safety of an enormous value in ships and steamers using charcoal as an insulator, but that my opinion is supported by the investigations of many men of high rank in the scientific world, as well as by well-authenticated instances of fires occurring from the spontaneous combustion of charcoal, both ashore and afloat.

The first authority I cite is that of Mr. F. C. Moore, president of the Continental Insurance Company, New York. In his work entitled “Fires,” published at New York (1877), Mr. Moore says, “Charcoal will burn when pulverised, or when finely divided in heaps. Twenty or thirty hundredweights of charcoal, in a state of minute subdivision, are almost certain to burn spontaneously. In an experiment made in France, under Government supervision, it was found that the inflammation occurs towards the centre of the mass, at about five or six inches below the surface. The temperature is constantly higher at this point than any other. In another instance, where small charcoal was thrown into a heap 10ft. square and 4ft. deep, containing two or three tons of charcoal, the temperature had increased in three days to 90°, though at first only 57° (that of the air at the time). On the sixth day it was 150°, and on the seventh day combustion had occurred in several places. The charcoal had been made ten or twelve days before the experiment took place, had been freely exposed to the air, and was not in any sense what is known as ‘freshlyburned' charcoal. When finely powdered, charcoal is more dangerous than when in sticks. Sixty pounds of powdered charcoal is sometimes a large enough quantity to ignite spontaneously. Lumps of charcoal, if moist, and subjected to a slight drying heat, will ignite.”

Professor C. J. Jackson (United States) reports, “Three times I have set fire to charcoal at temperatures below that of boiling water. My first experiment or observation was accidental. I was preparing, while at Bangor, Maine, for a lecture, in which I had occasion to show an artificial volcano. I took a tray filled with gunpowder, and laid it on the stove to dry. I then took a paper of pulverised charcoal, such as is sold by apothecaries for tooth-powder, the charcoal being wrapped in white paper, and placed it on the top of the gunpowder which was being dried upon the stove. Having occasion to go out, I took off the paper of charcoal and laid it upon the table. When I came back, in twenty minutes, I observed the paper smoking. The charcoal was completely consumed. During all this time the gunpowder remained on the stove unexploded. My next observation was this: While at work in my laboratory I had occasion to use a piece of charcoal for blowpipe experiments. I went down into my cellar and brought up a piece of light, fine, round charcoal suited for the purpose. It was

damp. I laid it on the top of a column stove to dry, directly beside a tin pan containing water which was not boiling, and which never did boil there. I took the charcoal off the stove and laid it on my table. A short time afterwards I discovered it was on fire all through the piece. I laid it aside, and it burned entirely to ashes. The theory of the ignition of charcoal under these circumstances struck me at once. Charcoal has wonderful porosity; it has the power of analysing air, and of absorbing the oxygen with comparatively little of its nitrogen. The pores of the charcoal were previously filled with moisture. The oxygen of the air was condensed in the charcoal, taking the place of the moisture. The condensation of the oxygen produced heat to ignite the charcoal. I repeated the experiment again, intentionally, watching it carefully, and with the same results.”

Professor Bloxam, one of the most eminent authorities on the spontaneous combustion of charcoal, says, “Charcoal absorbs mechanically into its pores nine times its volume of oxygen. The compression of a gas always evolves heat. Hence the temperature of the charcoal would be raised. If this goes on quicker than the heat is given off (charcoal being a bad conductor of heat, any heat generated in the interior does not escape), then we get spontaneous combustion.”

M. Violette, perhaps the most eminent of French authorities on the spontaneous combustion of charcoal, says, “The charcoals from different kinds of wood, when prepared at a nominal heat of 572°, spontaneously ignite between 698° and 734°, according to the nature of the wood producing them, but the product from the lighter woods burns quicker than that of the denser woods.” M. Violette goes on to say that “charcoals from the same wood, but prepared at increasing temperatures, spontaneously undergo combustion at very unequal degrees of heat.”

Dr. Ure says, “The higher the temperature at which charcoal has been made, the higher is its igniting-point; therefore charcoal made from light woods, such as willow and fir, all of which can be made at a temperature as low as 300° C., are the most dangerous, being both more absorbent and more readily inflammable.”

Mr. Dupont, the large American powder-manufacturer, states that “charcoal powdered and piled in a heap is liable to spontaneous ignition. He had suffered loss from this cause, and a similar accident occurred in Paris, when one of the wings of the Mint took fire through large quantities of charcoal stored in a garret.”

Mr. Hares, a recognised insurance authority, states that “charcoal is liable to spontaneous combustion, especially in a ground state, when left in heaps and exposed to damp.”

If further evidence be needed of the well-known and highly-dangerous liability of charcoal to spontaneous combustion, I am permitted to cite the opinion of Colonel Majendie, H.M. Chief Inspector of Explosions, in a letter to me from the Home Office dated 28th August, 1890.

Colonel Majendie says, “The liability of charcoal to heat and fire spontaneously is a well-known and firmlyestablished scientific fact, and has frequently formed the subject of experimental investigation. Several fires from this cause have come under our notice. So well recognised is this risk that there is a special rule in ‘The Explosives Act, 1875,’ as to allowing any charcoal to remain in a danger building.”

The general ignorance of the liability of charcoal to spontaneous combustion is the more surprising in the face of the provisions of “The Explosives Act, 1875,” some of which are as follows: “Charcoal, whether ground or otherwise, shall not be taken into any danger building, except for the purpose of immediate supply. No maker of gunpowder shall keep, or permit to be kept, any charcoal within twenty yards of any mill for making gunpowder.”

The foregoing opinions and experiments of eminent authorities show with sufficient plainness that charcoal is liable to spontaneous combustion, and therefore highly dangerous.

I shall now leave the region of scientific research, and proceed to cite instances of fires which have occurred afloat and ashore from the use of charcoal as the insulating-material, premising that many mysterious fires have occurred without any cause being assigned, owing to the prevailing ignorance of the liability of charcoal to spontaneous combustion, and to the difficulty of ascertaining the cause of a fire after the complete destruction of a building or ship.

The following memorandum of marine losses in steamers carrying frozen meat from New Zealand (which I have been kindly permitted to quote), by the Surveyor of the Canterbury Marine Underwriters' Association, dated Christchurch, New Zealand, 11th April, 1890, is sufficiently conclusive: “1. Steamer ‘Ionic,’ sailed November, 1883; fire took place in refrigerating-chamber; 800 carcases scorched, and 5,000 carcases damaged. 2. Steamer ‘Ruapehu,’ on fire (said to be) through steampipes. 3. Steamer ‘Selembria,’ sailed February, 1888; meat on fire; 12,000 carcases condemned at Monte Video, remainder condemned on arrival in London. 4. Steamer ‘Kaikoura,’ on fire (said to be) through steampipes.”

Subsequently to the above fires, the “Ashleigh Brook” arrived in London on fire (said to be) in her bunkers; 1,025 carcases consumed.

The steamer “Ionic,” lying in the London Docks, took fire on the 24th December, 1889, and again on the 26th December, 1889. In both cases the charcoal insulation was badly burnt, and without doubt caused both fires.

The “Moorish Prince” steamer, while lying in the South West India Dock, took fire on the morning of the 10th September, 1890. The steamer was laden with charcoal and timber, and (as reported in the London Evening Standard of the same day) from some unknown cause a large quantity of the charcoal took fire.

Towards the close of 1891, the P. and O. steamer “Rome,” lying in dock at Greenock to be lengthened, took fire. The fire was cabled as having been caused by her charcoal insulation. Though this was afterwards denied, “as believed to have occurred through a candle being left burning by one of the workmen,” it may be one of the “mysterious fires” where, for obvious reasons, any cause of fire is accepted rather than the true one.

In this connection it may be noted that the frozen-meat ships “Dunedin” and “Marlborough” (both insulated ships) were never heard of after leaving the New Zealand ports of departure. There can be hardly any doubt that both were burned at sea, with all hands, owing to the spontaneous combustion of their insulation.

I now come to the fire on board the iron frozen-meat ship “Timaru” (insulated with charcoal about two years ago). The “Timaru,” lying in Auckland Harbour, had been discharged, and was waiting for a charter, having nothing in her but some barrels of cement for stiffening. On the morning of the 21st September, 1892, the “Timaru” was found to be on fire in her charcoal insulation (the ship being fitted up for carrying frozen meat). Owing to exceptionally favourable circumstances, the fire was extinguished before very much damage had been done. Had the fire occurred in mid-ocean the ship would have been destroyed with all on board. In that case no evidence of the fire would have been forthcoming, and, as in so many other cases, the final and only report would have been, “Ship ‘Timaru’ never heard of.”

The fire on the “Timaru,” without any question or doubt, was caused by the spontaneous combustion of her charcoal insulation, as will be seen from the reports of the various official surveys held on board her immediately after the fire by Captain H. Worsp, for the Auckland Marine Underwriters' Association, and Captain M. T. Clayton, for Lloyd's Agent in Auckland, and for Lloyd's Registry, London. From these exhaustive reports I am permitted to make the following extracts:—

Captain Worsp says, “The fire on board the ship ‘Timaru’

was, in my opinion, due to the spontaneous combustion of the charcoal insulation.”

Captain M. T. Clayton says, “I examined the locality of the fire on board the ship ‘Timaru,’ and enclose plans of the situation. I believe the fire originated from spontaneous combustion (of the charcoal insulation). The fire burnt upwards from the charcoal, and nearly burnt through the deck before it was discovered.”

Mr. Rose, H.M. Collector of Customs at the Port of Auckland, also held an inquiry on the fire on the ship “Timaru,” and, after taking the fullest evidence, reports the fire to have occurred from the spontaneous combustion of the charcoal insulation.

There are now more than thirty steamers and six ships engaged in the New Zealand frozen-meat trade, with a tonnage of about 130,000 tons, costing, say, two millions sterling, and carrying yearly (including about two million sheep) exports and imports to the annual value of £12,000,000 sterling. These amounts involve an annual payment of about £250,000 per annum for insurance.

Will it be believed that every one of these steamers and sailers is carrying along with it an element—charcoal—proved by the experiments of experienced scientists to be liable to spontaneous combustion, which the numerous fires from this cause show to have long since passed out of the region of experiment?

The form in which charcoal is generally used for insulating purposes is in small irregularly-shaped pieces. In this form the interstices between the pieces of charcoal are filled with air, which renders the insulation incomplete, and which requires a large extra amount of coal to correct this imperfect insulation and keep down the temperature to the required point. When these air-spaces become partially filled by fine charcoal, resulting from the slow grinding action inseparable from the continual motion of the steamer, the dangers from spontaneous combustion are greatly increased.

In corroboration of the dangers arising from the spontaneous combustion of charcoal when used as the insulatingmaterial in ships or freezing-works on shore, I am permitted to make the following extract from a report upon evidence taken by the Insurance Association, Christchurch, New Zealand, on a fire in the Belfast Freezing-works, near Christ-church, dated the 5th November, 1888, kindly placed at my disposal by the insurance authorities there:—

The report by Mr. Secretary Madden to the chairman of the Insurance Association says, “In forwarding you the evidence in connection with the fire at Belfast, I have to call your attention to that of Huston, Glass, and others, who are

positive as to where the fire originated. Their evidence entirely upsets the theory that the fire originated from any sparks getting under the eaves of the building. It is very clear that it started in the ceiling of No. 5 freezing-room, which was composed, firstly of timber, then charcoal, and then sawdust. This being the case, had a spark falling on the roof (which was of iron) been the reason of the fire, it would have caused the sawdust to ignite. It is well known that had this occurred it would have smouldered for hours, and been seen. Apart from this, had such occurred the fire would have been first seen through the roof; whereas the evidence shows that such was not the case. Mr. Glass (chief engineer) says, ‘The fire had burnt a small hole in the ceiling of the cooling-chamber.’ This statement is corroborated by others. This brings one to the question, ‘What was the cause of the fire?’ Having carefully considered the matter, I am of opinion that it originated from spontaneous combustion (of the charcoal insulation).” In support of this conclusion the secretary quotes several well-recognised authorities, and concludes his report by stating that, “if (as these opinions prove) the fire at the Belfast Works did occur from spontaneous combustion, it is undoubtedly a question for very serious consideration not only in connection with freezing-works on shore, but also as regards vessels taking frozen meat to London.” This fire cost the insurance companies about £20,000. Three years ago a fire occurred at Hull in a cooling-chamber insulated by charcoal. On the 15th September, 1890, a fire occurred in a building used by the Chargeurs Meat Company at Havre, France, when 8,000 frozen sheep, and the refrigerating apparatus, were destroyed. Damage, £20,000. In both these fires the cause was reported as “unknown,” but is believed to be due to the spontaneous combustion of the charcoal insulation employed.

As yet the frozen-meat trade is only in its infancy. If, in the short period it has been in operation, so many fires have occurred, with charcoal and sheathing new and in good order, what disasters may not reasonably be looked for when the charcoal becomes more or less reduced to a powder—its most dangerous form—and when the wooden linings of the cooledchambers undergo the natural decay inseparable from the intense cold to which they are exposed on the homeward voyages, followed by the complete thawing on the outward voyages, and so permitting melted snow, moisture, air, and oil to enter the charcoal insulation! When a portion of the charcoal becomes sufficiently damp to enable it to analyse the air, oil, or water with which it may be brought in contact, it slowly condenses the oxygen, and becomes saturated with it during the subsequent drying process.

This subtle process may be slow. It is naturally very unequal in the time required for its completion, for, as M. Violette observes, “Charcoal made from various kinds of woods ignites spontaneously at different temperatures; made even from the same wood it ignites spontaneously under very unequal conditions.”

It is well known that freshly-burned charcoal is most subject to a speedier spontaneous combustion; but the conditions attending the spontaneous combustion of charcoal are uncertain and subtle, and their investigation has not yet been complete enough to enable a time to be fixed when a fire will certainly take place. The subtle process may require months or years to complete. Its conditions are necessarily unknown, and cannot be detected until, by the heat from a steampipe, or by the heat of the tropics, or in some other unexplained way, the point of combustion is reached, when a fire occurs.

We must consider that, through leakage, bilge-water, a few drops of oil, or from rats eating through the charcoal casing, the charcoal used for insulating may at various undiscovered points become damp; when that happens the first stage of the process begins. The next stage, as before stated, may be deferred for a short or a long period, but it is only biding its time. Its progress is necessarily unknown, and cannot be detected until, in most cases, long after the point of combustion has been reached. It is easy enough to understand how this dangerous process operates, but it is often impossible to ascertain either its commencement, development, or progress, till too late.

With charcoal as the insulator, immunity from fires, almost certain to occur sooner or later, cannot be secured. It is idle to say that many charcoal-insulated steamers make voyages without taking fire. Escape from a disaster for a longer or shorter period gives no guarantee that it will never occur if every steamer carries with it the elements of incipient destruction, any more than a man with heart-disease can ever be certain that, because he has carried the disease about with him for years with impunity, a sudden catastrophe will never strike him down.

Let but a frozen-meat steamer be burnt in mid-ocean in consequence of carrying so dangerous a material as charcoal for insulation, and not only will a great loss of property take place, attended by a great loss of life, but, unless all hands perish, the usual report at Lloyd's of ships lost under such conditions will be “Lost at sea, cause unknown.” But if a few survivors escape the perils of the fire and the sea to report the cause of the ship's destruction as having arisen from the spontaneous combustion of her charcoal, then shipowners and shippers may expect a general advance of insurance rates all

along the line, to be followed by an avoidance by passengers of all steamers carrying frozen meat. Nor will the matter end there, for in these days every passenger-steamer is provided with a charcoal-insulated chamber to carry its fresh provisions for use on the voyage.

It may therefore as well be remembered that it is by no means beyond the limits of probability that it may be the fate, sooner of later, of many or most ships and steamers carrying frozen meat or other articles in cooled-chambers insulated with charcoal to be burned at sea, if this highly dangerous material continues to be used for insulating purposes.

Gunpowder, which will not ignite except by a spark or light, is surrounded by precautions; yet, notwithstanding the accumulation of scientific opinions and experiments, and the occurrence of many actual fires demonstrating the liability of charcoal to spontaneous combustion, steamers and property aggregating more than a hundred millions sterling in value, together with tens of thousands of seamen and passengers, are every year sent to sea, carrying along with them charcoal, a material far more dangerous than gunpowder—so full, indeed, of the elements of catastrophe that public opinion is not likely to tolerate such a condition of things much longer.

It is evident, therefore, that the use of charcoal as an insulator is full of danger to all parties—steamship-owners, freezing- and dairy-works proprietors, insurance companies, and sea-going people generally. The dangers incidental to the sea are serious enough without increasing them in an unnecessary manner by sending ships to sea with such a dangerous article as charcoal on board.

Unless a safe substitute for charcoal be available, then great losses of life, of shipping, and other property, followed by much higher insurance-rates, lower prices for sheep or higher prices of meat to consumers, are looming in the not very distant future.

I should not have undertaken an investigation so arduous and unsatisfactory unless I had believed in the existence of a material as a safe and perfect substitute for charcoal, for he is but an indifferent doctor who tells you that you are suffering from a disease, but fails to point out a remedy.

For many years I have been acquainted with the peculiar properties of pumice, a product of New Zealand and of two or three other countries. In the course of my investigations I have made many careful experiments, with the result that I have ascertained that amongst the several kinds of pumice one or two varieties are suitable in the highest degree, when properly prepared, as a safe and perfect substitute for charcoal for insulating purposes, for the following reasons:—

1. Pumice, properly selected and prepared, is altogether

unaffected by heat, and is one of the best non-conductors of heat or cold known. One end of a piece of it, 2in. long and ¼in. square, may be placed in a gas-jet for two hours without sensibly raising the temperature at the other end, whilst a piece of iron of the same size becomes red-hot in half the time.

2. It is not in the least affected by the most intense cold.

3. It is unaffected by damp or moisture, never developing the smallest approach to heat-fermentation, never generating any fungoid growth, or taint of any kind.

4. It is absolutely free from the least tendency to spontaneous combustion. It cannot even be fused alone by the most intense heat.

5. Rats will not touch it.

6. Pumice is extremely light when properly selected and prepared, being about the same weight as charcoal.

7. It is perfectly clean, more satisfactory to handle than charcoal, and in case of accidental escape from the insulating-walls it does not blacken or soil, like charcoal, the frozen meat, or the bags which contain it.

8. In case of fire occurring, from any cause, in any one compartment of an iron steamer or ship, if the bulkheads be made double by an additional sheathing of thin iron at the back, and the prepared pumice be filled into the space, then not only do the bulkheads so filled in secure the original objects of strength, and safety from water, but these bulkheads so filled—with very little addition of weight—will prevent absolutely any fire occurring in one compartment from spreading through the bulkheads to the next compartments, with the further safeguard of the complete prevention of any heat from the boiler or engine compartments to the insulating—wills of the cooled-chambers, and removing one of the most dangerous elements of combustion from that cause where charcoal is used.

I have only to add that the use of carefully-selected and prepared pumice as an insulator, in place of charcoal, on all steamers and ships having cooled-chambers, will secure absolute and perfect immunity from fires from spontaneous combustion, besides rendering a fire on board arising from other causes more manageable by the absence of charcoal, which only adds fuel to the conflagration, whereas the pumice-filled bulkhead, as before described, presents an impenetrable barrier to its progress.

By the substitution of prepared pumice in steamers, or freezing-works on shore, in place of the charcoal now in use as the insulator, an absolute safeguard will be provided against all fires from spontaneous combustion; it will remove the uneasy feeling current among the better-informed insurance offices