THURSDAY, DECEMBER 30, 1880

PERUVIAN BARK

Peruvian Bark; a Popular Account of the Introduction of Chinchona Cultivation into British India. By Clements R. Markham, C.B., F.R.S. 1860-1880. (London: John Murray, 1880.)

“THE HE enterprise undertaken by me in 1859 of introducing the cultivation of Peruvian bark trees into British India and Ceylon is now an assured success." With these words Mr. Markham begins his preface, and a perusal of the convenient history he has put together of the gradual steps by which during the past twenty years this success has been reached, enables us to fully share the satisfaction with which they must have been written. Not merely has a cheap supply of febrifuge alkaloids been brought within reach of the fever-haunted population of India, but a new and highly-profitable industry has been opened to the planters of our tropical colonies, and the yield of an inestimable drug placed beyond risk of exhaustion.

Enthusiasm is in most enterprises essential to success. If a certain tinge of impracticability often accompanies it a moderate experience of human nature disposes us to regard this with a good deal of toleration. We may as well confess at once therefore that the pleasure with which we have studied Mr. Markham's pages would have been greater but for his insistance throughout on two grievances, in neither of which do we find ourselves in any way persuaded by his advocacy. One of these-the other is more serious, and must be adverted to further on-is irritating in inverse proportion to its importance. The names of genera employed in systematic botany are Latinised forms, very arbitrary, and often, it must be allowed, unscholarly in their construction. But they are symbols or dockets under which scientific information can be arranged. If there is one thing about which botanists, of whatever nationality, are agreed, it is that the docket, having once been promulgated and brought into use, shall not be meddled with. It may be abolished or merged in some other, but being a mere symbol it cannot be tampered with without disturbing all kinds of mechanical aids to study, such as indexes and catalogues, and so adding to the worry of life. From a literary point of view the correction of Cinchona into Chinchona may be desirable, but the trouble of having two spellings in circulation is too great a price to pay for the mere satisfaction of literary propriety. It cannot be said therefore that this is merely a literary question like such spellings as those of diocess and chymistry affected by the Times, while from a technical point of view it has been already discussed and conclusively decided against Mr. Markham in the pages of this journal.

The genus Cinchona—as we must still beg leave to call it-includes all the plants at present known to yield quinine and allied alkaloids. It has rather more than thirty species, some of which however are medicinally valueless, while the rest vary individually in the amount and character of the alkaloids they yield. The native habitat of the genus is very restricted; it is only found on the Andes between 10° N. and 19° S. lat., and between VOL. XXIII.-No. 583

2500 and 9000 feet of elevation. Besides this the several species are closely limited to particular portions of the general area.

The native inhabitants seem to have set little store on the febrifugal properties of the cinchonas, and indeed to have been little aware of them except in the neighbourhood of Loxa, where a Jesuit was cured in 1600 of a fever at Malacotas by Peruvian bark, and to this day the local prejudice against its use is very strong. In 1638, however, the Countess of Chinchon, wife of the Viceroy of Peru, was cured of intermittent fever by bark sent by the Corregidor of Loxa. The remedy, whose reputation was now established, was carried by her to Spain in 1640, and became known as Pulvis comitissæ. In 1670 it was sent to Rome by the Jesuits and distributed to members of that order throughout Europe. Hence it came to be called Jesuit's bark, and it is interesting to find that its merits became accordingly a party question between Protestants and Catholics.

For more than a century (till 1776) the only bark met with in commerce was that brought from the neighbourhood of Loxa. This was called Quinquina, from the Indian name quina-quina, quina meaning bark, and the reduplication the possession of medicinal properties. The plant producing the bark was described by Linnæus under the name of Cinchona officinalis, to be rechristened afterwards by Humboldt and Bonpland Cinchona condaminea, a change correctly rejected by Mr. Markham, following Sir Joseph Hooker, and, be it remarked, on precisely the same grounds as those on which the rechristening of the genus as Chinchona must also be rejected. As early as 1735 Ulloa represented to the Spanish Government that the Loxa forests could not long survive the reckless treatment to which even then they were subjected. And this was in spite of the intelligent efforts of the Jesuits, who endeavoured to enforce replanting as a religious duty. The Loxa bark, eventually distinguished as Crown bark from being reserved, when other kinds became known, for use in the Royal Pharmacy at Madrid, is represented in old collections of Materia Medica, such as that of the College of Physicians, by massive fragments which must have been detached from very old trees. Mr. Markham tells us that it is now only found in commerce in the minutest quills. As the Loxa bark became scarce the search after other supplies of cinchona bark was stimulated. The botanical expedition of Ruiz and Pavon sent by the Spanish Government in 1777 resulted in the discovery of seven species of Cinchona, yielding gre bark, near Huanuco in Northern Peru. Mutis, another Spanish botanist, believed that he first detected a Cinchona in Columbia in 1772, though a resident in Bogota challenged his claim to priority.

The well-known "red bark" of the slopes of Chimborazo seems to have been known early in the last century, and later to have found its way into European markets, though it was not till 1857 that the plant yielding it was clearly identified by Dr. Klotzsch. The yellow or Calisaya barks of Bolivia, first discovered by Haerke in 1776, did not become of commercial importance till 1820, when quinine, the most important active principle of Peruvian bark having been isolated by the French chemists, Pelletier and Caventou, yellow bark was recognised as richer in it than any other kind.

K

It is not necessary to follow in detail the interesting account given by Mr. Markham of the recklessness with which the natural supplies of Cinchona bark were drawn upon. The inconvenience of a precarious dependence upon the South American forests has for at least forty years occupied the attention of scientific men in Europe. Royle, in 1839, urged the introduction of Cinchonas into India, and pointed out the Nilgiri Hills as a suitable locality. The Dutch botanists had been no less urgent that the experiment should be made in Java, and Hasskarl was commissioned to proceed to Peru in 1852 to obtain seeds. In this he succeeded, but the bulk of the seeds eventually proved to belong to a species worthless medicinally, which was afterwards named C. Pahudiana. He also obtained, by the aid of a Bolivian named Henriquez, 400 plants of the yellow bark, C. Calisaya, only two of which unfortunately survived in Java. The mishaps of the Dutch enterprise cannot be followed here, instructive as they are to any one interested in the cultivation. A happy accident, to be presently alluded to, was a kind and well-deserved turn of fortune in its favour, and a greater measure of success than could ever have been hoped for now seems assured to it.

The Government of India in 1852 first proposed the introduction of cinchona into that country, and several abortive attempts to effect it were made with the aid of the Foreign Office, but without success. In 1859 Mr. Markham was officially employed by the present Lord Derby, who was then Secretary of State for India, to undertake a mission to South America for the purpose. His previous travels in the Cinchona region, though for ethnological and not for botanical inquiry, and his knowledge of the Spanish and Quichua languages singularly fitted him for the task. The plan laid down by him was extremely comprehensive, and has at last been fully carried out, or nearly so. It was nothing less than the introduction into India of all the species of Cinchona yielding bark of known commercial value. This plan was adopted as it was à priori uncertain which kinds would turn out best adapted for Indian cultivation, and it was desirable that all should be tried; it involved no less than five distinct expeditions to the different districts of the Andes already mentioned.

Mr. Markham visited himself in 1860 the yellow bark region in Southern Peru and Bolivia, accompanied by a young gardener named John Weir, recommended by Messrs. Veitch. The plants collected reached England in fifteen Wardian cases, but the heat of the Red Sea was fatal to them and they all eventually died. A supply of seed which Mr. Markham had arranged for at Caravaya arrived in India in 1865 and germinated satisfactorily.

Mr. Pritchett, who had travelled in the Huanuco district, was employed to make a collection of the grey bark plants, and to these also the Red Sea was fatal, but the loss again was retrieved by the safe transmission to India of seed which grew well. The red bark region was visited, at the suggestion of Sir William Hooker, by the well-known botanical traveller, Dr. Spruce, who was residing in South America at the time, and he was accompanied by Robert Cross, a Scotch gardener, recommended by the Kew authorities. The plants collected by Dr. Spruce were more fortunate, and reached India in good condition in 1861 under Mr. Cross's charge.

This skilful collector then returned to South America and obtained the seed of the crown bark from the Loxa forests, which reached India in 1862 and germinated abundantly. Before returning to Europe he visited the Columbian forests in 1863 and secured seed of Pitayo bark (C. Pitayensis), which however had lost its vitality before it arrived in India. He was therefore sent again in 1868, and this time secured both plants and seeds, which were transmitted to India in a living state. The only remaining kinds of importance which had not been introduced into India were the Calisaya de Santa Fé, yielding soft Columbian bark, and Cinchona cordifolia, yielding hard Carthagena bark; to procure these Mr. Cross was despatched on another mission, from which he returned in 1878, bringing cuttings of both kinds, and these were successfully propagated at Kew, which had indeed in every case been made the depôt for the receipt of the successive consignments and their despatch to India. The Carthagena bark is now well established in India, Jamaica, and it is hoped in Ceylon. But the fate of the Calisaya de Santa Fé is still doubtful, as one consignment succumbed to the heat of the Red Sea, which is so great an obstacle to the transport of plants, intolerant of great heat, and no news as to the second instalment taken out in charge of Mr. Cross has yet reached this country.

We must but very briefly hurry over the interesting pages in which Mr. Markham describes what has been done in India. Red bark has everywhere taken the lead. Next to this, in the Nilgiris, crown bark has succeeded best; the other kinds have made but little progress. Unfortunately little care seems of late to have been taken in Southern India to keep the different kinds distinct, and as the species hybridise very freely it is not easy to say what some of the plants actually in cultivation precisely are. In the Himalayas, however, besides red and crown bark-plants, C. Calisaya (yellow bark) and C. micrantha (one of the species yielding grey bark) also do well.

The share taken by Kew in this important enterprise enabled the advantages secured by the Indian Government to be extended to other tropical possessions in the Empire. Sir William Hooker was allowed to transmit a share of the seeds and plants to Ceylon, Jamaica, Trinidad, Mauritius, and St. Helena. In the three latter islands the cultivation has made but little progress; in the first it is now one of the staple resources of the planters; while in Jamaica the crown and red bark bring in an annual revenue to the Government, which leaves an ample surplus after paying the whole expenses of the botanical department.

One of the most singular incidents in the whole story has still to be told. Mr. Charles Ledger, who had long resided in South America, hearing of Mr. Markham's enterprise, employed a native servant, Manuel Mamani, to collect seed of the best Calisaya or yellow bark tree. Four years elapsed before he succeeded, as each year the blossom of the trees was destroyed by frost. These seeds were transmitted to London to the care of Mr. Ledger's brother, and it is believed were offered to the Indian Government, who refused to purchase them. Half was eventually sold to the Dutch Government and half to Mr. Money, a planter on the Nilgiris. This fortunate purchase has put quite a

new face upon the cultivation in Java. The bark of some of the trees has yielded as much as 10 per cent. of quinine; and the news of this remarkable result has produced much the same effect on Cinchona planters in Ceylon and Southern India as the discovery of a gold-field on the inhabitants of an Australian city. The Java officials have however behaved with singular liberality in the matter, and in the course of a few years it cannot be doubted that Ceylon will be abundantly supplied with this valuable kind, which, there seems reason to think, may prove to be a distinct species. Part of the seed sent in the first instance to the Nilgiris seems to have found its way to Sikkim, and the Government plantations there are

The steps taken at Mr. Markham's instance for the introduction into India of the most important rubberyielding plants of the New World have been from time to time recorded in our pages. We have only to repair one inadvertent omission on Mr. Markham's part, and point out that the transmission of the Para rubber plant to India was secured by the exertions of Mr. Wickham, as recorded in the Kew Report for 1876, p. 8.

PRACTICAL BLOWPIPE ASSAYING Practical Blowpipe Assaying. By George Attwood. With Seventy-four Woodcuts. (London: Sampson Low, Marston, Searle, and Rivington, 1880.)

if at all inferior to that possessed by the Dutch.

The Government of Bengal have effected an enormous saving by using, in hospitals and dispensaries, instead of quinine imported from Europe, the febrifuge manufactured at the Sikkim plantations. The Government estimated that in consequence, by the end of 1879, “the plantations will have cleared off the entire capital that has been invested in them."

And this leads us to what is really the painful feature in Mr. Markham's book. He complains in repeated and in bitter terms of the want of justice which has been shown to those whom he employed in the business of collecting. "Those who did the work have not received fair recompense for most valuable services." It is rather singular to find that he adduces in support of this statement the case of Mr. Ledger, who was not even in any way commissioned to do what he did. But the remuneration which his actual agents received was the ground of no complaint on their part, and was in point of fact liberal compared with that which is given to the collectors who are constantly employed by the great nurserymen, and who too often lose their lives in their arduous pursuits without the satisfaction of feeling that they are doing so in an enterprise like this of lasting utility. But we fear that if Mr. Markham's assistants have reason to complain the blame must, on his own showing, be laid at his own door. He tells us (p. 271): "The system I adopted was . . . to include very slight remuneration in the original agreements. Thus the loss to Government would be insignificant if the work was not executed satisfactorily. If, on the other hand, the arduous tasks were successfully performed . . . I anticipated no difficulty in obtaining fitting recognition for such distinguished services." We leave our readers to judge of the probability of such a scheme answering Mr. Markham's expectations. We may go further, and ask how the claims would have stood if, notwithstanding all the pains that were taken, the cultivation of Cinchonas had fared in India—as might even have happened—no better than it at first did in Java.

But there are many other things pleasanter than this which we should like to touch upon if this review had not already run to an inordinate length. So many Englishmen are now in one way or other interested in colonial industries that it will be strange if this interesting book does not find as many readers as it deserves. Besides a complete history of the Cinchona enterprise in the Old World, it gives, in an appendix, accounts of some other South American vegetable products, notably india-rubber.

part of the author. At the very outset, in the Introduction, we meet with strange statements. Mr. Attwood divides the elements into those which are of commercial value and those which are of no commercial value. In the latter class we find Uranium and Tungsten; surely the author does not intend to deny the value of pitchblende and wolfram. He classifies zirconium among the non-metallic elements.

The first part of the work describes the reagents and apparatus; the second, we are told, contains the modes of determining any one of the sixty-four well-recognised elements, and in the third part we have the methods adopted by the author for making quantitative assays by the blowpipe. Finally, Part IV. contains some tables showing the English and American values of gold according to its fineness, and the value of gold coins in the United States.

The apparatus employed is much the same as that recommended by Plattner. Like Neumann, Mr. Attwood very wisely uses riders with his balance instead of the very small weights supplied by some of the other Freiberg opticians; but the balance would be improved by the addition of a movable arm for shifting these riders. The steelyard devised by the author will probably be of use to explorers. From practical experience with the batea I can fully endorse all that is said in its favour, but why are the merits of the iron pan ignored? It has the advantage that it will stand rougher usage than the batea. Again, for washing a sample of tin ore nothing will beat the Cornish vanning shovel.

I regret to see no mention of the useful little pastilles and crucibles made out of charcoal powder, proposed by Griffin thirty or forty years ago and adopted by Plattner. Col. Ross's aluminium plate for sublimates seems also to have escaped Mr. Attwood's notice.

With reference to the list of reagents I must remark that the author does not name all the reagents which his tests require, whilst others are inserted which he does. not appear to put to any use. I should be glad to know what he means by inserting "nitrous acid" among his reagents. This is not a misprint for "nitric acid,” because that acid has been already named.

The plan of the second part of the work is not one which I should recommend. It simply contains a list of tests for the various elements, but gives no systematic scheme for making the examination of an unknown substance. I fear that the "direct" method advocated by Mr. Attwood will often prove a very tedious one. Many of the tests themselves are not so complete as they

ought to be. In describing the tests for barium it is said that the bead "can be flamed," but no explanation is given of the process of flaming. The capital test for bismuth with potassium iodide and sulphur is entirely ignored.

I now come to the third part, which treats of quantitative assays. Mr. Attwood's plan of making a check assay in every case with a small quantity of the pure metal is certainly calculated to give the operator confidence in his results. The author adopts 1 grain as the amount of ore to be taken for an assay. I think he would have done better to have followed Plattner and used the

French weights, because there is less chance of making errors where each milligramme means I per cent.

For the silver assay Mr. Attwood employs pieces of ordinary charcoal instead of the far more convenient and portable charcoal crucibles designed by Plattner. He also describes a crucible assay for silver ores, which does not appear to possess any advantage over Plattner's scorifica

tion method.

OUR BOOK SHELF

Über die von den Trichopterenlarven der Provinz Santa Catharina verfertigen Gehäuse. Von Dr. Fritz Müller. Archivos de Museu national. Vol. iii. pp. 99-134, and 209-214. Rio de Janeiro, 1880. (Aus dem Portugieischen übersetzt von dem Bruder des Verfassers, Dr. Hermann Müller in Lippstadt.)

DR. FRITZ MULLER has for some years been engaged upon an investigation of the habits of the Caddis-flies of Santa Catharina, and has shown extraordinary skill in breeding these insects, a matter always difficult, and especially in the case of those that inhabit running water. The results of his researches were foreshadowed in various Transactions of the Entomological Society of London notes published in the Zoologischer Anzeiger and in the for 1879.

But it was well known that the extended information and figures would be given in the Rio de Janeiro Archivos. As this publication is somewhat difficult to obtain, and as most of us are not familiar with Portuguese, Dr. Hermann Müller has conferred a great boon by publishing a translation of the paper (accompanied by the two folded plates) in the Zeitschrift für wissenschaftliche Zoologie for the present year (pp. 47-87, plates iv. and v.). It is needless to state that the details are of the greatest interest, and we have here the most important contribution to the natural history of Trichoptera that has appeared since the publicaand worked out in a far superior manner. We cannot here even allude to most of the many marvels of insectarchitecture and habits that Dr. Fritz Müller has revealed.

Some neat little retorts have been designed by the author for distilling ores of mercury and amalgam, but he does not mention Küstel's assay.

On coming to the tin assay we have the peculiar statement that silica may be separated from tin ore by boiling t with hydrochloric acid. "The assay being finely powdered, the silica is dissolved." "The dissolved silica is decanted off" (p. 158). Cornish mine agents will be surprised when they are told that, in order to obtain correct results, it is necessary to wash or van as much as 5 lbs. of an ordinary tin ore (p. 159).

Under the head of nickel no mention is made of the valuable ores from New Caledonia.

Small mistakes are numerous. The size of a box is said to be "twelve inches square" (p. 3); we note also: "a most useful addenda” (p. 24); "chloride of ammonia" (p. 33); "manganite" instead of manganate (p. 53), and permanganate (p. 54). The term "raw iron" is used frequently instead of "pig iron," and shows that the author has copied Cornwall's translation blindly. Coal, anthracite, and graphite are said to "volatilise" when heated in the platinum spoon (p. 82). Sieves are made with 2000 holes per "linear" inch (pp. 100 and 137). In the description of cupellation (p. 106) we read: "The lead parts with portions of its oxygen to the copper and other base metals."

In conclusion I think that the value of the book would be increased if a list of errata et corrigenda were inserted, correcting some of the errors which, I regret to say, impair its general usefulness. C. LE NEVE FOSTER

Some of the most interesting are the numerous forms of Helicopsyche, which build little sand-cases so like shells that they have been described as such; those Dentaliumlike cases, originally noticed by Aug. St. Hilaire as Grumicha, which name our author retains; those instances of parasitism (or worse) in which a larva of one species dispossesses that of another of its house and converts it to its own purposes; those very numerous forms of Hydroptilidæ, the most minute of all Trichoptera, with cases of the most varied and wonderful structure; above all, that most interesting fact that the rain-water which collects at the bases of the leaves of some Bromeliaca has a special fauna of its own, including at least one Caddis-worm. The descriptions of these and many others will be read with delight by every biological student; and we hope Dr. Müller will follow up the paper by records of further discoveries, for here, as in all his works, the evidences of superior powers of observation

strike one on every page.

The plates are excellent, and aid much in a realisation of the descriptive portion. Dr. Müller's artistic powers are so marked that we cannot but regret he has not furnished details of the form and structure of the perfect insects also, which would have greatly aided systematists: in fact the perfect insects are only alluded to in a casual

manner.

Voyages of the Elizabethan Seamen to America. Thirteen Original Narratives from the Collection of Hakluyt, Selected and Edited, with Historical Notices, by E. J. Payne, M.A. (London: De La Rue and Co., 1880.) WE do not quite understand Mr. Payne's reason for publishing this selection from Hakluyt's classical collection of voyages. The selection is, however, judicious, and cannot fail to be interesting, and at the same time instructive, to those who desire to become familiar with the first beginnings of English conquest in America. Mr. Payne's familiarity with the subject of British colonisation, as exemplified in his excellent little "History of such a selection as the present. His brief Historical European Colonies," specially qualifies him for making Introduction enables the reader to understand the special significance of the voyages contained in this volume. He

shows the various causes in operation at the time to instigate such voyages, causes mainly political and commercial. Other influences were however at work, not the least of which was "the total transformation

which astronomy and geography had undergone" during

the sixteenth century. The narratives here given are those of Hawkins's and Frobisher's three voyages, Drake's voyages of 1577 and 1585, Gilbert's voyage of 1583, Amadas and Barlow's voyage, 1584; Cavendish's first and last voyages, and Raleigh's voyage to Guiana. Prefixed to each narrative is a short historical introduction.

LETTERS TO THE EDITOR

[The Editor does not hold himself responsible for opinions expressed by his correspondents. Neither can he undertake to return, or to correspond with the writers of, rejected manuscripts. No notice is taken of anonymous communications. The Editor urgently requests correspondents to keep their letters as short as possible. The pressure on his space is so great that it is impossible otherwise to ensure the appearance even of communications containing interesting and novel facts.]

Black Sheep

THE following extract of a letter from Mr. Sanderson of Chislehurst, who permits me to publish it, seems worth placing on record. It relates to the former frequent appearance of spotted or black sheep in the Australian flocks, as long as animals thus coloured were of use to man, although they were never, as far as Mr. Sanderson knows, separately bred from, and certainly not in his own case. On the other hand, as soon as coloured sheep ceased to be of use they were no longer allowed to grow up, and their numbers rapidly decreased. I have elsewhere assigned reasons for the belief that the occasional appearance of dark-coloured or piebald sheep is due to reversion to the primeval colouring of the species. This tendency to reversion appears to be most difficult quite to eradicate, and quickly to gain in strength if there is no selection. Mr. Sanderson writes:-"In the early days before fences were erected and when shepherds had charge of very large flocks (occasionally 4c00 or 5000) it was important to have a few sheep easily noticed amongst the rest; and hence the value of a certain number of black or partly black sheep, so that coloured lambs were then carefully preserved. It was easy to count ten or a dozen such sheep in a flock, and when one was missing it was pretty safe to conclude that a good many had strayed with it, so that the shepherd really kept count of his flock by counting his speckled sheep. As fences were erected the flocks were made smaller, and the necessity for having these spotted sheep passed away. Their wool also being of small value the practice soon grew of killing them off as lambs, or so young that they had small chance of breeding, and it surprised me how at the end of my sheepfarming experience of about eight years the percentage of coloured lambs produced was so much smaller than at the beginning. As the quantity of coloured wool from Australia seems to have much diminished, the above experience would appear to be general." CHARLES DARWIN

The Nature of the Chemical Elements DR. ARMSTRONG'S article in NATURE, vol. xxiii. p. 141, has brought to my mind some calculations I made more than a year ago to test a theory I had long previously entertained. Most of us who have paid much attention to the subject are agreed that the elements are capable, under exceptional circumstances, of profound chemical change. Mr. Lockyer is searching, with success as it appears, for contemporary evidence of this by examining the condition of the solar surface. The other line of evidence is historical, and turns mainly on the classification of the numerical values of chemical symbols. It is of course only with the latter that I have to deal.

The classifications proposed by Newlands and Mendelejeff are comprehensions of much similar preceding work. They appear to me to be faulty in two ways: (1) on account of the seriously large number of elements they wholly fail to include, and (2) because of the strong stress they lay upon arithmetical series of a rough per saltum character. As I do not know of any real case of per saltum chemical change, I do not think the elements should be classified on such a basis. What is wanted is a system capable of including with exactness and not mere approximation - the whole of the elementary num

bers; that system to be represented in the mathematical symbols of ordinary chemical change, and therefore free from a per saltum character. I have to a great extent succeeded in finding such a system, and the results of testing it at many points are as follow:-1. There is pro

bably only one fundamental form of matter; and this, as has

been previously supposed, yields our ordinary elements and many others by ordinary polymerisation. 2. Almost all the elementary numbers have been tried, and, with the exception of H and CI, which are a little troublesome, they fall into order very exactly. 3. This order exhibits no discontinuity, and is similar to a case of ordinary chemical change. 4. There is clearly an upper limit to this order; in other words, elementary numbers of more than a certain magnitude appear to be impossible.

Sir B. C. Brodie's method is really a classificatory one; and I with others had been very desirous to read the Third Part of the Calculus, in which it was promised ampler play. It will be a matter for much regret if his premature death should have prevented this. But what he did publish was sound and sure: the first real symbols chemistry has yet enjoyed, and the only ones hitherto proposed whereby the process and the results of chemical change admit of unitary as well as kinetical representation. EDMUND J. MILLS

Smokeless London

As I hope soon to have an opportunity of reading a paper on this subject before a scientific audience I need not occupy your valuable space by replying to your correspondents of last week in detail. I may say however that the scheme has been carried out in practice at a gas-work to which I shall afterwards refer. When it was found that the apparatus for making gas on an extraction of six hours was insufficient for supplying the wants of the long winter evenings the distillation was stopped when gas had been removed to the extent of 50co cubic feet per ton. The larger quantities obtained from the coal per unit of time and the superior illuminating power obtained per unit of volume tided over the difficulty and rendered the existing plant sufficient. No practical obstacles were discovered in discharging the retorts. I do not think the difference between an extraction of 5000 and 3333 cubic feet per ton would make a material change in this respect. Mr. Mattieu Williams points out a much more serious obstruction in the plethoric indifference of the gas companies. In reply to E. K. F. I may say that the fuel resulting from a uniform extraction of 3333 cubic feet per ton is practically smokeless if it is taken hot from the retorts and immediately quenched with water. Westminster, December 27 W. D. SCOTT-MONCRIEFF

Colliery Explosions and Coal-Dust ACCEPTING Mr. Galloway's view that in many mines the extent and destructiveness of colliery explosions are due to the distribution of coal-dust in the air, may I suggest the possibility of preventing the explosion from spreading beyond the sphere of the fire-damp by sprinkling the floors throughout, at certain regular intervals, with mineral oil? A shady road, with one such sprinkling, may be kept free from dust for several weeks during the summer, and the corridors of a mine, not being open to wind and rain, would of course remain wet for a longer period. A saucer filled with dust and treated with mineral oil will retain the oil for months even when exposed to sun and rain. The mixture of coal dust and oil is quite uninflammable. The experiment may perhaps be worth trying in one of the drier coal-mines. December 27 R. RUSSELL

Geological Climates

PROF. DUNCAN is under the impression that the claim of Araucaria Cunninghami to have flourished at Bournemouth during the Eocene, rests on "a bit of a leafy part of a tree," and that this bit is " squashed." The foliage is however abundant there, occurring almost wherever vegetable remains are found, from the east of Bournemouth Pier to half a mile beyond Boscombe. In one place, where a bluff is literally full of it, the diarticulated branchlets are perfect, and not in the least degree compressed. Again, the determination was not made by Prof. Haughton, but rests upon my statement that this foliage and that of A. Cunninghami cannot be distinguished one from the other. That it is Araucarian foliage I am perfectly satisfied; but whether the existing Australian species is identical and unmodified, must remain doubtful until other