I have had occasion to make a large number of experiments on such discharges taken alone and diluted with much water, with the view of testing the destructive nature of these liquids and mixtures upon the life of fish, and the general results of the inquiry I purpose to lay before the Section.

The discharges from the paraffin oil-works are of the following nature:

1. Crude petroleum and shale-oil escaping from the crude oil-casks, either when full or when empty, when the drainings leak away into the surrounding soil and thence to the drains.

2. The condensing water from the worms of the crude and refining stills, which often passes away impregnated with paraffin oil.

3. The spent acid liquor which has been used in acting upon the crude petroleum or shale-oil.

4. The spent alkaline liquid or soda which has been employed in acting upon the oil which has been previously treated with acid.

Besides these there is the accidental overflow of the retorts, both during the first redistillation of the crude oil, and subsequently in the distillation of the refined oil, and which can hardly be altogether provided against.

The drainings from the oil-casks, when the latter have been emptied and are exposed to the sun, are considerable when a number of casks are stored together, and the oil which percolates through the soil is liable not only to ooze through the ground, but when rain falls, the oil floats thereupon, and is thus carried into the ordinary drains. Any material damage to rivers, however, from this cause may be lessened by providing proper surface drains, which carry all the oily water to traps where it settles, and the oil may be removed from the surface whilst the water is run off underneath. The condensing water from the stills is liable to be impregnated with paraffin oil from the leakage of the pipes, which is greater when the pipes are of cast iron than when they are constructed of malleable iron. Of course any excessive leakage is quickly arrested, but there is generally that taint communicated to the water which, independent of the lesser proportion of oxygen dissolved in the water as compared with ordinary river-water, renders the water more or less deleterious to the health of fish.

The spent acid liquor and the spent soda-liquor, however, are the most serious discharges which, either regularly or occasionally, escape from paraffin oil-works, and their influence upon the health and life of fish are much more decided than the paraffin oil itself."

The spent acid liquor consists of the sulphuric acid which has been added to the crude oil, accompanied by tar products, including picoline and other Lasic oils, and to which the acid liquor no doubt owes part of its poisonous properties. Whilst now the material in question is to some extent utilized by separating the tar, and either mixing it with spent oak bark, or sawdust, and using it as a fuel, or by distilling it into pitch, yet occasionally the acid liquor is discharged into a neighbouring stream. It is a black tarry liquid of the consistence of molasses, with a somewhat sulphureous odour, and a very small quantity added to water confers poisonous properties upon the latter.

In one example I found the spent acid liquor, which was collected somewhat diluted with water, to possess the following powerful effects upon fish:

1. When the liquor was taken by itself and fish immersed therein, they were dead in five minutes.

2. When the liquor was diluted with three times its volume of good stream water and fish introduced into the mixture, they were killed in ten minutes.

3. With one of the liquor and twenty of water, the fish died in fifteen minutes. 4. One of the liquor and 100 of water, killed the fish in fifteen to twenty

minutes.

5. One of the liquor and 1000 of water was poisonous to the fish in two hours, whilst

6. In one of the liquor to 10,000 of water, the fish were not killed by their immersion in the mixed liquor for twenty-four hours, but were apparently sick and prostrate.

The spent soda-liquor which has been employed in treating the oil which had been previously acted upon by acid is necessarily decidedly alkaline and caustic in

its nature. It has extracted from the oil and retains in solution more or less carbolic acid and its homologues, and the poisonous nature of the spent soda-liquor is doubtless materially augmented by the presence of these acids.

One sample of this soda-liquor which was flowing from a paraffin oil-work, and which contained extra water, proved destructive to fish in ten minutes; diluted with three parts of water, it killed fish in twenty minutes; with twenty of water, the fish were dead in twenty-five minutes; with 100 of water, the fish were killed in thirty minutes; diluted with 1000 of water, the soda-water was destructive to fish in twenty hours; whilst in 10,000 of water the fish were not killed but were apparently slightly sick. Experiments were made with crude shale-oil and the refined oils obtained therefrom, and with crude Pennsylvanian petroleum, and the refined oils extracted from it. The crude shale-oil was destructive to fish when taken in the proportion of 1 of the oil to 1000 of water-the crude oil being more energetic in its action than any of the others, then in succession the lubricating oil, the burning oil, and the lighter spirit.

The Pennsylvanian petroleum was not so powerful in its poisonous properties as the shale-oil employed in the experiments. The crude shale-oil, in the proportion of 1 to 1000 of water, was poisonous to fish in twelve hours; whilst the crude Pennsylvanian oil in the same proportion did not kill the fish for twenty-four hours. The refined oils acted in a corresponding manner on fish. Thus the refined shaleoil, in the proportion of 1 to 1000 of water, killed the fish in twenty-four hours; whilst the refined Pennsylvanian oil did not prove destructive for two days.

The importance of this subject will probably soon be greater than what it is at present, as the manufacture of crude paraffin oil in conjunction with gas has already been introduced into one of our gas-works in Scotland.

The coal used is the Newbattle gas or Cannel coal, which yields when distilled in ordinary gas-retorts, at a bright cherry-red heat, about 11,000 cubic feet of gas, with an illuminating or photogenic power of thirty-four standard sperm candles for every five cubic feet of the gas burned during every hour. When distilled, however, at a low or black-red heat in larger retorts, as carried on in ordinary paraffin oil-works, the coal yields only 3000 to 3500 cubic feet of illuminating gas, with the photogenic power of thirty candles for every five cubic feet burned during the hour, so that two-thirds of the total quantity of gas capable of being yielded by the coal is sacrificed; but in place thereof there are obtained about 60 gallons of crude paraffin oil with a specific gravity of 900 to 905. The gas-works in question are virtually crude paraffin oil-works in which the gas is utilized; and as the change in the mode of working the coal appears to be profitable, there is every reason to consider it likely that other gas-works will follow the example, and become virtually crude paraffin oil-works with refineries attached thereto.

On an Extraordinary Iron Stone. By Dr. T. L. PHIPSON, F.C.S. &c. The author alludes in this paper to a journey which he made during the year 1865 in the principality of Waldeck (Germany), and gives an account of the mining district which he visited there. About twelve English miles from the mineral springs of Wildungen, in the region where the schists are upheaved by greenstone, containing lodes of copper ore, lead ore, and barytine, with some zinc blende, he met with a very remarkable ironstone which is distinct from the fine red hematite that abounds in these districts, by the presence of a considerable amount of magnetic oxide of iron, some specimens yielding as much as 23 per cent., and when smelted give about 59 per cent. of iron of exceedingly fine quality. This mineral occurs in a quartz lode, is crystallized in the rhombic system, and as brilliant as steel. It gives a dark purple powder. The red hematites of the same district all contain a little magnetic oxide, varying from 2 to 4 per cent. and even more.

On the Origin of Muscular Force in Animals.

By Dr. LYON PLAYFAIR, C.B., LL.D., F.R.S.L. & E.

The author reviewed the recent experiments of Fick and Wislicenus on this subject. These physiologists ascended the Faulhorn, after having subsisted for thirty-one hours on cake made of starch fried in fat, and they found that they

ascended the height of 2000 metres, with an evacuation of urea which, converted into muscular substance, did not represent more than half the actual energy expended in the ascent. The author pointed out as the main objections to this experiment (1) that the period of production of urea is not necessarily the period of its elimination; (2) that when starch and fat are used as food alone, the nitrogen of the alvine dejections, usually only one-twelfth that in the urinary secretions, augments so much as sometimes to be equal in amount to the latter. With respect to the first objection, E. Smith has shown that lowering of the barometer and thermometer retards the evacuation of urea, and these conditions were obviously present at the top of a high mountain. The amount of urea passed for twelve hours before the ascent was 46 grammes; but it was only 38 grammes in the six hours of the ascent and six hours after it; while it fell to 32 grammes in the subsequent twelve hours, although a hearty meal had been taken. The result was not easily explicable on Liebig's views, that muscular force is produced by muscular waste; but it was equally difficult to explain on the view that the urea is the mere representation of the waste of muscle due to the friction of the machine, whose natural fuel is non-nitrogenous [food; for the experiments show that when the friction of the machine was largely increased by the work performed, the amount of urea actually diminished, instead of increasing proportionally to the work.

The author then entered largely into the proofs offered by experience in feeding man and animals, that albuminous diet must be offered in proportion to the work demanded. He showed that there was sufficient potential energy present in the ordinary supply of albumen to men to account for the work performed. But he did not deny that non-nitrogenous diet might, in the absence of such albuminous supply, be temporarily used for the production of muscular force. Such vicarious action is common in the body. But this admission did not interfere with the view that the normal food and fuel of muscles consists of albuminous bodies, which must constantly be supplied to produce sustained effort, and to prevent corporeal deterioration.

On a New Process in the Manufacture of White Lead. By PETER SPENCE.

On some Phenomena connected with the Melting and Solidifying of Wax. By C. TOMLINSON, F.C.S.

When melted bees-wax containing a small portion of a very fine powder, such as that of plumbago, is poured into a shallow tinned-iron tray and allowed to cool, the wax breaks up into a number of hexagonal figures more or less regular, the boundaries being marked by the plumbago. The lines of the hexagons are formed by the mutual pressure of rings of plumbago powder thrown off from cylindrical or polygonal centres of the wax in cooling. Even in deep vessels of melted stearine or grease, containing particles capable of floating about in it, and of being carried to and fro by currents, an irregular network is formed by the particles arranging themselves on the surface in lines. There appears to be on the surface a movement of the grease from the centre to the sides of each of these polygonal figures. The figure varies with the material, and may be shown during the cooling. It may be seen on castor-oil and other fatty bodies; but not on spermaceti or crystalline fatty bodies. The figures are produced by a kind of local convection; that is, convective currents rise and sink in various parts of the mass, so that from many points at the bottom of the vessel rising currents are set up, and as the surface of the oil cools by exposure to the air, these cooler portions sink from various points of the surface, so that, instead of one central rising current, and one circumferential sinking current as in ordinary cooling, many small rising and sinking currents are established. Hence the surface becomes divided into many spaces, in the centre of each of which a current of warm oil is rising and around the circumference of which the cooler oil is sinking. Each of these systems tends to form a cylinder, with a rising central and a sinking circumferential current, and the contact of the boundaries of such cylinders produces a series of polygon-shaped systems. If the surface be very still, and there be no tendency in the oil to crystallize as it cools,

nearly perfect hexagons are formed, and as the circumference of each hexagonal system is cooler than its centre, the floating particles are first arrested at the circumferences, and gradually accumulate there, giving an hexagonal appearance to the surface as the mass cools. In a crystalline material the tendency to assume its peculiar crystal would probably overcome these currents before the mass became cool.

The second part of the paper referred to the passage of an electric spark through melted wax, &c. The early electricians remarked that a non-conductor, when melted, became a conductor. Faraday found that when such substances were fused and tested by their power to transmit a voltaic current, in no case did the current pass, unless accompanied by polarization of particles and decomposition. The same seems to be true for frictional electricity. The substance to be tried was contained in a glass bulb about 2 inches across in the widest part, and about 3 inches high, fitted with corks through which pointed brass wires were passed, or one pointed and one knobbed. On hanging such a bulb by its wire to the prime conductor of an electrical machine, connecting the lower wire with the earth, and setting the machine in action, a most vivid spark plays between the wires, striking out, as it were, from an anvil a multitude of smaller sparks, and lighting up the whole of the bulb and liquid in a remarkable manner. The smaller sparks, which apparently fill the bulb, are globules of gas, arising from the decomposition of a portion of the liquid, and illuminated by the principal discharge. When the point and bulb are far apart, the discharge is in the form of a brilliant rippled line of light, also accompanied by decomposition of the dielectric. The effects vary with different substances, and also change with the cooling of each substance. Spermaceti, cocoa-nut oil, lard, and solid paraffin are well adapted to these experiments, and also such fluids as castor-oil, balsam of copaibæ, paraffin oil, turpentine, and benzole. It was not found possible to pass a spark through melted camphor. By holding a bulb containing the solid over a spirit-lamp, the solid may be melted in a few minutes. The phenomena form good class experiments.

On a Phosphatic Deposit in the Lower Green Sand of Bedfordshire.
By J. F. WALker.

On a Proposed Use of Fluorine in the Manufacture of Soda.
By WALTER WELDON.

When sulphate of sodium is treated with hydrofluoric acid, one half of the sulphate is converted into bisulphate and the other half is transformed into fluoride. Upon this fact of the reaction between sulphate of sodium and hydrofluoric acid yielding, without any destruction of sulphuric acid, a compound almost as readily caustifiable as carbonate of sodium itself, the author believed that it would prove practicable to base a manufacturing process by means of which soda should be produced, not only, if not exactly without the use, at any rate without any consumption of sulphuric acid, but actually without the consumption of any materials whatever excepting salt and coal, all the reagents employed being recovered for use over and over again continually. One method by which this object could be accomplished was described as follows. It comprises four operations, the first of which consists in the production of sulphate of sodium by double decomposition between chloride of sodium and sulphate of magnesium, having associated with it at least one atom of water, the products of this reaction being, besides sulphate of sodium, hydrochloric acid and magnesia. The second operation consists in treating two equivalents of sulphate of sodium with one equivalent of hydrofluoric acid, whereby one equivalent of fluoride of sodium, which for the most part precipitates, and one equivalent of bisulphate of sodium, which remains in solution, are formed. The third operation consists in the decomposition of the fluoride of sodium obtained in the second operation by means of the magnesia obtained as one of the results of the first operation, the products being caustic soda and fluoride of magnesium; and the fourth operation consists in the decomposition of this fluoride of magnesium by means either of the bisulphate of sodium obtained in the second operation, or of its second equivalent of sulphuric acid, separated in any conve

nient way, with production of sulphate of magnesium, with which to repeat the first operation, and hydrofluoric acid, with which to repeat the second operation. All the reagents employed for the transformation of salt into soda by this method are thus continually reproduced, the only materials consumed being the salt and a small quantity of fuel. The author also described some briefer methods than the above of transforming salt into soda by way of the intermediate production of fluoride of sodium.

GEOLOGY.

Address by Professor A. C. RAMSAY, LL.D., F.R.S., &c., President of the Section*.

SINCE I last had the honour of acting as President of the Geological Section a custom has crept in of opening the meetings of the various Sections with presidential addresses. I have, however, been called upon unexpectedly, and rather late in the day, to occupy this chair, while I was busy with a multitude of other avocations, and I have not had the time to prepare an address; nevertheless I shall endeavour to the best of my ability to say a few words upon the state of opinion upon various subjects connected with physical geology, so as, possibly, to prepare in some degree the minds of persons, who are not thoroughly conversant with all branches of the science, for topics that may, perhaps, be touched upon in some of the papers to be brought before us. The great question which underlies much that concerns geologists is whether the economy of the world as we now see it represents in kind, and partially or altogether in degree, the average economy of the world as it has existed in time past, as far as it can be traced by reference to rocks and their contents as they appear at the surface, or as deep beneath the surface as we may dare to reason upon within the limits of presumed legitimate inference.

After people had thoroughly made up their minds that the world consisted, as far as the outside of it is concerned, of two classes of rocks-igneous and aqueousit was for a long time the fashion to attribute most of the chief disturbances which the crust of the earth has undergone to the intrusion of igneous masses. The inclined positions of strata, the contortions of the formations in mountain-chains, and the existence even of many important faults-in fact, disturbance of strata generally, were apt to be referred to direct igneous action operating from below. But a closer analysis of the rocks founded on careful surveys, not of a little area here, and a little area there, but on surveys of kingdoms and continents, has tended to disprove these old-fashioned ideas, although you may constantly see them brought up again and again in a certain class of popular works, and sometimes even in memoirs by authors who ought to be better informed than merely to repeat the notions that we find in common-place popular works on geology.

Now, if we look at those British formations in which igneous rocks are most generally developed, what do we find? Go first to North Wales, to the Lower Silurian strata. which are to a great extent intermixed with igneous rocks. There, instead of finding great masses that broke through the stratified crust of the earth and tumbled the strata into confusion, the igneous rocks consist chiefly of beds of felspathic lava and ashes of great thickness interstratified among the Lower Silurian strata, with here and there bosses of porphyry, which may sometimes represent, as I think, the underground nuclei of old volcanoes of Lower Silurian age; but the mountainous character of the country is due, not to the direct igneous action of that period heaving up the rocks. On the contrary, all the rocky masses of which the region consists, both igneous and aqueous, have been disturbed and thrown into great sweeping undulations formed of curved strata, thousands of feet thick, by those agencies, whatever they may have been, that at a later date pro* This address was very imperfectly taken down in shorthand, and the speaker has since corrected it, and supplied the omissions of the reporter, to the best of his ability, from memory.