jelly. I endeavour to apply that to making a similar manufacture. Here is a specimen.[Producing the same.] I tried to produce the same effect as I did with Macintosh's process; it was in December, and it has been laying in that state ever since. There are two pieces; the upper part is a piece of the original cloth; the under piece consists of the two cemented together. I tried to dry it in a sand bath several days. The process of softening the caoutchouc in spirits of tnrpentine, and then adding linseed oil, is not similar to Mr. Macintosh's in the slightest degree. In the first place it is utterly decomposed. I thought it remained theoretically, but I tried an experiment to determine. 1 placed some Indiarubber in a metallic vessel, so that it should be exposed all the time to the temperature of the boiling oil, and this is the result; though it has been so long in this state you will find it is not dry, and, probably, never will dry: it is much more of the nature of birdlime. Mr. Serjeant Wilde. This is birdlime, gentlemen. You know it, I see.

Do you know whether there are any other modes of obtaining coal-oil except by distillation from coal?-Coal-tar will also produce it. However, from whatever source it comes, it is, speaking chemically, the same substance; and whether more or less pure, I should still treat it as the same substance, and give it the same name of coal oil? Undoubtedly, it is known by other names, but coal-oil or coalnaptha is the term it is generally known by.

Cross-examined by Mr. Rotch.

I am not aware that the name has changed at all since former times. In trying these experiments I sent to a dry-salter for it; I cannot say where I should have sent for it in the year 1823; perhaps to the gas-works. When I say it has become better known, I mean it is in more extensive use. I think nobody in 1823 would have doubted what coal-oil meant. In asking for this, my assistant stated, that it was coal-oil for dissolving caoutchouc, to ensure it of a pure quality more effectually to answer the purpose, as described in the specification; the specification itself states, that in proportion to the purity of the oil the process is better.

You

are directed in the specification to take a larger quantity of that which is not pure: it was for that reason (to guide me in the quantity) that I wished to get the best quality. I am well acquainted with gas-works, and have observed this very collection of coal-oil floating on the water of the gasometer; it is well known, it is stated, in all the works upon the subject. In a work of great authority by Dr. Hewit, in an able article, you will find it stated, that the petroleum floats on the water of the gasometer. Petroleum is mentioned by Dr. Hewit as floating on the surface

of the ammoniacal liquor. I should draw no distinction between the term petroleum and coal-oil under such circumstances, as petroleum drawn from the manufacture of gas in my mind accurately describes what is otherwise called coal-oil or coal-naptha. I should not call coal-oil in its pure state, uncombined with any bituminous matter, petroleum; but when it is so described, I should know what is meant. I do not consider the matter which is floating on the gasometer to be petroleum; I believe it to be coal-oil, but not in its pure state; I have never had an opportunity of trying to dissolve caoutchouc in the coal-oil in the state in which it is found on the surface of the water in the gasometer. The solution which is in the little gally-pot, which has been handed round, when evaporated is reduced back again to the substance of Indiarubber; there is nothing in it but caoutchouc and coal-oil. If there were two pieces of cloth with this mixture interposed and the solvent evaporated, nothing would remain between the two pieces of cloth but pure caoutchouc. I am not aware of any apparatus being constructed in the manufacture of gas for the purpose of collecting this coaloil in a pure state. I have no doubt that the gas-works provide means of manufacturing this for some purpose of commerce; but I do not know it from actual observation, dare say there are many extensive manufactories of coal-oil now in operation that receive the coal-tar as manufactured in the gas-works for the purpose of so converting it, but I do not know it-I have no doubt of it. A great deal of the coal-oil is produced from coal-tar, as well as the other products of the gas-works.

Re-examined by Sir Frederick Pollock.

I

In my judgment, the substance that is to be used is clearly pointed out by the specification.

The Attorney-General.-It may be convenient that we should now examine a specimen of the defendant's manufacture.

Mr. James White examined by the AttorneyGeneral.

About the latter end of October I went to the shop of Ellis and Everington, in St. Paul's Church-yard, by the direction of Mr. Blunt, the plaintiff's attorney, to buy a waterproof cloak; I asked for one of Macintosh's water-proof cloaks; they at first said they had not any, and recommended me to buy one which they produced of their own manu facture, stating, that various complaints had been made of Macintosh's. I bought one of each; they at first said they had none of Macintosh's, but they eventually produced one. I have now one, that one that they said was their own manufacture. I cut off some pieces of this cloak myself, and de

livered one to Mr. Garden in Oxford-street, and one to Mr. Cooper of Blackfriars-road, and one to Mr. Phillips of St. Thomas's. Hospital.

Cross-examined by Mr. Serjeant Talfourd.

I am sure that they told me the other cloaks were manufactured by themselves; they said they had bought the interest of a person in the patent, and my impression is, that they mentioned the name of Fanshawe, and that this was manufactured according to Fanshawe's patent. It is labelled "Fanshawe's Improved Patent India-rubber Waterproof Cloak."

Richard Phillips, Esq., examined by Mr. Serjeant Bompas.

I am Lecturer on Chemistry at St. Thomas's Hospital; I have seen the specification of Mr. Macintosh's patent, and have carried through the process mentioned in that specification. The specification is such that I could clearly understand the mode in which it was to be applied; and I applied the mode described in the specification to the manufacture of those articles that I now produce. That is a piece of silk, and here is the same water-proof; there is a piece of blottingpaper, and here is the same water-proof; these are made exactly in pursuance of the specification. I have for several years known the substance called coal-oil; it has been generally known in commerce under that

term.

I sent for some to Cassell's works, Mill-wall, Poplar. Mr. Cassell is a person who prepares this oil and purifies it. I do not know him personally. When it was produced, it was the substance I had before known. I have not been much accustomed to gas-works, but I have been there occasionally. Coal-oil is one of the products of coal when distilled. If coal-oil is wished to be purified, it is re-distilled. Re-distillation is a mode of purification which is commonly known by all chemists. Coal-oil is an extremely volatile substance; its nature is not at all changed by re-distillation; it is more volatile than coal-tar. If mixed with coaltar, it can be separated by re-distillation. Ammoniacal liquor is one of the products of coal in destructive distillation. The coal-oil is lighter than the ammoniacal liquor. I tried some experiments, according to Clarke's receipt, in the proportions of the substances that were given to me. 66 To one ounce of caoutchouc, eight ounces of spirits of turpentine, and seventy ounces of linseed-oil." The effect of the linseed-oil heat being applied, was to decompose the India-rubber. I put the caoutchouc in a different vessel, and then immersed the vessel in oil, and heated the oil, consequently the India-rubber which is here contained, was exposed to the temperature of the heated oil, and I found it had undergone

I

a great change: the India-rubber which was in the oil underwent a similar change. When the India-rubber is wholly or partly decomposed, it does not retain its elasticity, it becomes semi-fluid. I find that it adheres to the finger, and becomes almost as tenacious as birdlime, and cannot be dried again so as to restore it to India-rubber. It is rendered more fluid by the change it undergoes, but it cannot be rendered solid again. I did not try whether linseed oil or grease produces any effect on the India-rubber when cold. have got some specimens of the effect in applying the substance which I thus procured according to Clarke's plan, to, some fabrics. (Producing the same.) This was made fairly according to Clarke's directions. I tried it at different times in boiling; for instance, after the first two hours, another portion three hours, and then another after three hours more. I heated it at different periods. At which ever period I took it, it did not answer the purpose of Macintosh's patent, as I think will be evinced by these specimens. Some of these are done singly. Here is one which is done double, but you observe they have not adhered together; putting them by, they separated; and it immediately ran through this stuff, although it is very thick. Here is a piece more, part in its original state, and part where it has ran through. (Witness produced the specimens.) I have seen an account given by a person of the name of Weisse. Forming the best judgment I can, and having the materials given without the quantities, in my judgment, they could not form a substance that would produce the effect of Macintosh's. I received a piece of a cloak from Messrs. Blunt, Roy, and Blunt; a piece of the cloak the last witness bought; it bears so great a resemblance to Macintosh's, that I can see no difference. It is a double texture, and caoutchouc is employed in the same situation with respect to the double texture, as Macintosh's. Here is a piece of the caoutchouc I obtained. I put the piece into coal-oil, which dissolved the India-rubber which was then in that material; and I got the India-rubber from it, that satisfies me that the cloak had been made with a solution of India-rubber. In my judgment, these are precisely the same materials.

Cross-examined by Mr. Serjeant Wilde. I think I knew this article coal-oil, very soon after Mr. Macintosh took out his patent.

Re-examined by Mr. Serjeant Bompas. This is a specimen, made according to Clarke's specification; I immersed some linen into the preparation which we call Clarke's for a minute or two, and hung it up to dry in a dry place covered from the wet, but in the air: I left it there twelve days; and after that I exposed it again, in a situation calculated to dry it if it would dry. I did not apply heat,

because it is not directed to be applied in the specification. I should now call it dry; although some parts of it are not. This is another specimen which has been made seventeen days longer. The one which is nearly dry is a single fabric.

John Thomas Cooper, Esq., examined by Sir William Follett.

I am a Professor of Chemistry at Westminster Medical School. I have seen this specification of Macintosh's; I tried, according to the specification, to make the manufacture as there described. I proceeded entirely according to the process mentioned in the specification-nothing else to guide me, and I have some of the specimens of cloth here, showing the result. I succeeded perfectly in making a fabric impervious to water and air. I tried it both on cloth and paper; cloth on one side and cotton on the other. I sent for the coal-oil myself, to Cassell's manufactory, where they distil or purify coal-oil. These are bottles of the varnish, which have been prepared from the different oils. This is Cassell's oil, with bottle rubber. These are some of the specimens which I have tried with the coal-oil from Cassell's and the India-rubber with which those cloths have been cemented. I tried some experiments on what is called Clarke's patent. I followed the recipe which was given in the affidavit of Clarke, which was sent to me, and made some of Clarke's varnish I was not able to make any thing from the directions which would answer the purpose; the cloth experimented on is

pappy in some places; neither is the fabric impervious to air or water, and the Indiarubber has undergone a total change, a total destruction. Here is some of the Indiarubber which was put in the oil while boiling, and you observe it is quite changed. I immersed it in the boiling oil. Coal-oil is perfectly well known; I have known it sixteen or seventeen years at least, I have seen it at the gas-works, swimming on the surface of the ammoniacal liquor; and what I ob tained for the purpose of experiment at the gas-works was dipped off with a ladle, from the surface of the ammoniacal liquor. I tried that with the caoutchouc, according to the mode as described; and the varnish so produced is equally effective for the purpose of manufacturing fabrics of this sort.

The

coal-oil was not re-distilled; it was just dipped off from the surface of the ammoniacal liquor. The coal-oil is made pure by the distillation; it is not necessary to have a larger quantity of it to produce the effect, but it requires a greater quantity of crude oil to dissolve the same quantity of India-rubber. I have called it crude oil to distinguish it from the oil that has been re-distilled; the effect is the same, except that it makes the

fabric a little more stiff in consequence of the tarry matter that it leaves behind. You will find that that piece is not so flexible as the other. The purer the oil the better, and so says the specification. The mode of purifying this coal-oil is a thing perfectly well known to chemists; it did not require any deep science to know how to pursue it, nor any direction in the specification—any body at all acquainted with the subject would know how to set about it.

Cross-examined by Mr. Serjeant Wilde. I distilled coal-oil myself, think, about sixteen or seventeen years ago, I cannot exact tell when; it was that which was obtained at that time in small quantities from the surface of the gasometer-tanks. I collected some lately from the South Metropolitan Works in the Kent-road-about a quart. I went to the place and procured it myself; it was not procured from the gasometer, it was procured from the surface of a very large tank. I had not made any application on the subject of obtaining it before I went to get it. I did not do it myself, it is a nasty, dirty operation; I stood by and saw it done, some of the men did it.

Metallic Lighthouses.-Mr. Samuel Brown proposes employing bronze or cast-iron in the construction of lighthouses, instead of stone. He seems to have made out that a bronze lighthouse would be incomparably cheaper than a stone one, that it would be more secure against dilapidation or subversion by the waves, that the lights would be better protected from the spray by which they are Occasionally extinguished, that it could be erected in one-twentieth part of the time, and in situations where a stone structure is impracticable. It has been proposed to place a lighthouse on the Wolf Rock, near the Land's-End, a position where it would be exposed to the most violent storms of the Atlantic; and a plan was drawn up for the purpose by Mr. Stevenson, who holds a high rank in this department of engineering; which plan, Mr. Brown thinks, would require 15 years for its execution, and cost 150,000l. Mr. Brown undertakes to erect one of bronze, 90 feet high, which would answer the purpose as well as the stone one of 134 feet, for 15,000, and to complete it in four months.Scotsman.

Communications received from Mr. Tait-Mr. Harris-I. S.-A Constant Reader.

Patents taken out with economy and despatch; Specifications, Disclaimers, and Amend. ments, prepared or revised; Caveats entered; and generally every Branch of Patent Business promptly transacted. Drawings of Machinery also executed by skilful assistants, on the shortest notice.

LONDON: Published by J. CUNNINGHAM, at the Mechanics Magazine Office, No. 6, Peterborough-court, between 135 and 136, Fleet-street. Agent for the American Edition, Mr. O. RICH, 12, Red Lion square. Sold by G. G. BENNIS, 55, Rue Neuve, Saint Augustin, Paris. CUNNINGHAM and SALMON, Printers, Fleet-street.

SHALDERS'S FOUNTAIN-PUMP, Sir,-There has been much said for and against my new rolling principle in pumps, in your popular work." First, Mr. Hay (vol. xiii. p. 357), and many others since, have clearly proved that the principle is good in theory; and now that I am at last able, I hope you will permit me to state a few facts, in order to show to the public that it likewise proves extensively good in practice. The predictions respecting its limited operation, and the frailty of the connectors, I am happy to say, are practically proved to be wholly untrue. Many impatient gentlemen were quite confident the new principle would never raise water 100 feet high; never. theless, it is successfully employed in raising water to more than double that height. And notwithstanding the mischievous opposition which this mariner's guardian angel has had to encounter, it has preserved some ships' cargoes as well as lives. Too various, even only to name, are now the different purposes of application of the fountain-pump; therefore, a few cases will suffice to prove they are not expensive to keep in order when well fixed at first, whether used for extensive or

limited purposes. Neither the passive nor the active cones are subject to wear, therefore need no remarks; but practical proofs were wanting to establish the durabilty of the flexible cones, or the connectors, to the satisfaction of such parties as wanted to raise large quantities of water to different elevations. A superior effect has ever been manifest with the new frictionless pump over the old friction-pump; so that, in fact, what would be the expense for wear and tear of the connectors was the only question that remained to be settled.

Now mark well the results. For the following four important purposes the connectors on an average have not cost three shillings a year for each machine, and have been tested from 10 to 100 feet perpendicular height:

The first fountain-pump that was sold raised the water 10 feet high, at Mr. Doughty's, Brockdish, to supply one of the largest tanneries in Norfolk. The first connector lasted thirty-five months.

A fountain-pump at Mr. Thornton's, Beccles, raised the water for his brewery about 30 feet; the first connector lasted seventeen months, and others used since have lasted considerably longer.

A treble-motion horse fountain-pump at Messrs. Youngs and Burt's, Norwich, raised the water for their brewery nearly 50, and sometimes more than 100 feet. The first connector of the three failed in the twentieth month, when the second was almost worn out, but the third continued perfect.

A treble-motion horse fountain-pump at Messrs. Taylor and Dyson's, Diss, Norfolk, has raised the water for their brewery about 100 feet for more than twenty-one months; and the connectors were all found perfect upon a recent examination.

A single horse with this machine raises 80 barrels of water in an hour, which is equal to 400 barrels raised 20 feet, or 4,800lbs. raised one foot high per minute.

Thus, then, the stability of this great hydraulic invention has been proved conclusively; fully justifying the opinion of Dr. Birkbeck, that "the fountain-pump is free from the liabilities and defects of the common friction-pump, and approaches to a perfect hydraulic-machine."

So perfect is the new pump, that when the column of water which is wanted to be lifted weighs 995lbs., a weight of 1,000lbs. at the opposite extremity of a true balance will preponderate and raise that column of water; while so defective are those on the old principle of construction, even in their best condition, that 73 per cent., upon an average, over and above the weight of the column of water which is wanted to be lifted, will but just overcome the friction resistance.

If a fountain-pump deliver 20lbs. of water 10 feet high, or 2lbs. of water 100 feet high per stroke, and a friction pump deliver 12lbs. of water 10 feet high, or 2lbs. of water 60 feet high per strokefour men of equal power, one man at each pump, will work all day long at the same speed. Make a thousand fair trials, and this in round numbers will be about the result whilst both pumps continue in their best condition.

But in practice the gain is considerably greater, for the packing of the friction. pump soon begins to wear away, and then a part of the water repasses the piston; whilst the fountain-pump continues to perform for years without the slightest variation, and the gain is still greater when sand, &c. is intermixed with the water.

If the stroke, or rather the dip, be