SPECIAL INTERVIEWS.

New Zealand Herald, Volume XXXIII, Issue 10034, 22 January 1896, Page 3

SPECIAL INTERVIEWS.

FIRES FROM FREEZING CHAMBERS.

PUMICE INSULATION.

A NEW ZEALAND INVENTION. A long succession of fires at sea, on ships carrying frozen meat, are now very generally conceded to have arisen through the charcoal insulation employed on such vessels. Only a few weeks ago the latest iustance came to hand, And as Mr. J. C. Firth had discovered and patented a preparation of pumice for use on board ships, and at freezing works, which, for the reason of its safety, is superseding charcoal, a Herald representative saw him for the purpose of gaining further particulars. SPONTANEOUS COMBUSTION. " What first directed your attention," asked our representative, " to the matter of insulation." " The occurrence of fires since the commencement of the freezing industry in New Zealand some twelve or thirteen years ago, first drew my attention strongly to the danger of charcoal. That thore was a danger I had been previously well aware. This danger arises from the unique property which charcoal possesses of absorbing within itself, and analysing within its pores, oxygen _ from any gas or liquid with which it may come in contact. This has long been known to scientific men. Charcoal will absorb nine times its volume of oxygen, that is, one cubic inch of charcoal has a capacity of absorbing nine cubic inches of concentrated oxygen. Whenever the absorption takes places, spontaneous combustion is absolutely certain to follow. The period for this absorption may bo longer or shorter. Looking at the fact that when charcoal has once obtained any oxygen from any subject preseuted to it, that oxygen is never released, and the absorption goes on constantly, sooner later spontaneous combustion is bound to occur. The subject, it will thus be seen, is of very acute importance to the seagoing public, for though combustion may be deferred for one, or even ten years, it must occur sooner or later, directly"the point of saturation is readied. I may mention another faculty in connection with oxydised charcoal—that is, it will burn without contact with the external air, because the oxygen contains within itself the elemeut for combustion. It follows from this that a fire may be burning in the charcoal insulation of a steamer for one, two, three, or four days before it is discovered. In the case of a fire which was discovered on a large steamship when 300 miles from Sydney, the engineer said he was led to believe, from tho presence of carbonic oxido, that the steamer had been on fire when alongside the Circular Wharf."

11l addition to that fire Mr. Firth instanced many more, in some of which there were very narrow escapes, and in one at least it was only after most strenuous exertions for i\ days that danger had beeu averted, aud then only after filling the holds with water.

RECURRENCE OE FIRES. "In several instances," went on Mr. Firth, who was evidently well versed in the history of tires from charcoal insulation, " where water has been pumped into the holds the charcoal has taken fire again." " Youspokejustnowof carbonic oxide." " Yes, and that is another serious danger. It is formed by the charcoal fires, and being heavier than the air sinks to the lower portion of the holds. Formerly officers and crew, on the discovery of a fire, took off the hatches and went below to ascertain the cause, in nearly every case with most serious danger to life, now it has become the custom as I have said to fill the holds with water. It is not necessary for me to give a long list of the charcoal fires, at sea—they are well enough kuown. But the London Economist recently called attention to the matter, asking if it was necessary that a great catastrophe, involving serious loss of life should first take place before Colonial Governments would take any measures to prevent the fires.

MR, FIRTH'S INVENTION. "Andyour invention, Mr. Firth?" " The recurrence of these fires," said the gentleman named, " led me to think of their prevention for ten years past. After closest attention, and many experiments, I discovered that of all substances, a certain kind of pumice, prepared in a particular manner, was an absolute preventative, and with it there was no danger whatever from spontaneous combustion. After completing my researches I patented the process for preparing it, and also patented the prepared product, and erected works of large capacity, and at very great cost, near Raugiiiri. In these works the pumice is subjected to the most intense heat, which kills all germs of every description. At this point I may say that I have been concerned in mechanical, mining, and milling enterprises tor a great number of years, and I have met with more difficulties in overcoming the obstacles pumice preseuted than in respect to anything else I have ever dealt with. I found it to be the most impracticable substance I ever handled. Its being so very light, destroyed its power of gravitation, and so prevented it being treated as one would treat wheat, or flour, or ore. It possesses anoher property which gave me the utmost difficulty, that was its supreme non-conducting power. This will be best explained by saying that pumice, when found, _is more or less damp. In that state it is but a moderate nonconductor. In order to make it a firstclass conductor every particle of moisture must be driven out of it. To an inexperienced person that would seem easy enough. Instead ot that it proved most difficult. I should weary you by describing the innumerable experiments I made in order to get rid of the water from the pumice, and make it the perfectly non-conducting material as I now produce it. These obstacles, which appeared almost insurmountable, however, are overcome, and the very qualities which were the most difficult to treat are the best."

CONSERVATISM. " Have you found any difficulty in getting your prepared pumice insulation adopted?" queried our representative. " Well,yes." was the reply, "very great difficulty. Englishmen, and Colonial Englishmen as well, however democratic, are highly conservative in a good many things. I had difficulties enough in inventing the process, and adapting machinery. But these difficulties were as nothing to those met when I first started the attempt to substitute my pumice insulation for charcoal. However, by an amount of perseverance, which, now that I have won, astonishes me, I have at last demonstrated the very great snpe riority of pumice over charcoal, not only as absolutely non-combustible but as I prepare it entirely free of all organic mattery of every kind. The advantage of this will be seen from the fact that charcoal forms a nidws or breeding ground for germs and microbes of various varieties, the propagation of which is helped by the amount of oxygen in the charcoal. The non-germinating qualities of pumice are not the least the least important. What is known as the "loss of bloom" of meat at arriving in-London, and the development of mildew in a more or less pronounced form is probably due to the development of germs by charcoal. In prepared pumice there can exist no vegetable or insect life: it is entirely free lrom organic matter, and produces no decay whatever.

COMING TO THE FRONT. [ "Have you any objection to stating to what extent you have succeeded in introducing your pumice insulation ?" " None at all. Since I got fairly to work— although many of the freezing works in this country had been completed before I began —I have sold and delivered something over 50,000 sacks, and have now very large orders in hand."

"Have you had practical opinion of those connected with freezing works of your pumice ?" "Yes. In every case where a sufficient time has elapsed tor a sufficient test to have been made ; and in all the opinions have been highly satisfactory. The latest is from Mr. John Cooke, chairman of the Riverina Freezing Works, Deiiiliquiu. I value this the more, because Mr. Cooke may justly be regarded as one of the chief founders of tho frozen meat industry, both in New Zealand and Australia." ATMOSPHERIC AND SOUNp INSOLATION. " Has your pumice insulation been proved advantageous to the dairy industry, as I understand that butter to [be of the primest 'piality, it must be made and stored at a low temperature "My pumice insulation has been applied in many dairy factories, amongst others by Messrs. Reynolds and Co., of this city. With reference to your idea that the primest butter must be made at a low temperature, you arc so far right that the best dairy experts say that butter ought not to be made or stored at a higher temperature than 60deg, to Gsdeg. F." "Is there any other purpose for which you find the insulating properties of pumice valuable.'

"There is a very important one. Seeing that the majority of houses throughout Australasia are covered with iron, the upper rooms are rendered unpleasantly hot or unpleasantly cold. A layer of pumice placed betwixt the roof and the lining hoards equalises this. It has also complete sounddestroying properties, which give occupants of bedrooms and other apartments freedom from sound disturbances and absolute privacy. For insulating telephone boxes it has proved a perfect success, removing entirely the confusion arising from the transmission of all sorts of sounds. " Have you ever brought yonr invention to the notice of the shipping companies at Home?:-

"I have. But here again the Conservative instincts of Englishmen came in opposition to any change. In spite of this, however, many of the leading steamship companies are considering the question, and my pumice insulation is being adopted. The British steamship interest is one of most powerful organisations in the world. It is impossible to dictate to it, and very naturally demands and receives a great deal of consideration, in what it may justly consider the proper management of its own business. I have never interfered with that. The only parties whose influence will have any weight in the shipping companies will be, in the first instance, the insurance companies; next, the frozen meat companies, who may very well object to send their meat in ships at higher rates than necessary, and at a higher rate of danger. The other parties intimately concerned in this great question are t , -. , > seagoing public, both passengers and crew. When a great disaster occurs, then tho Imperial and Colonial Governments will be compelled to interfere. 51" Amongst the many discouraging circumstances which have confronted me in the prosecution of these experiments," said Mr. Firth, "I may perhaps mention one little instance in an opposite direction. When I had got my works iuto operation ,1 was met by a drayman, whom I did not know, who addressed me thus,' Mr. Firth, I have had to take some of your machinery from the railway ; I have watched theso many tiros, and the efforts you have made to suppress them with great interest; I hope you will succeed; I believe you will, for you have made one of the greatest discoveries of the ago.'" That was nob bad for a New Zealand drayman.