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had been first noticed in America in 1861, and was patented in England by James Young in 1865. Thorpe and Young took 3 kilos. of paraffin wax obtained from shale and distilled it in an iron mercury bottle connected with a second by a bent tube carrying pressure gauge and stop-cock. The distillation was carried out over an open coal fire, one bottle containing the paraffin being heated, whilst the other acted as a condenser. In about four or five hours the distillation was completed, the pressure throughout being kept at 25 lb., and a magma of oil and unaltered paraffin resulted, which could be liquefied completely by the warmth of the hand. Four litres of liquid hydrocarbons were obtained, and on a preliminary factionation gave :

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Repeated distillations of the portion boiling below 100° C. resolved it almost entirely into three fractions:

(1) 320-38 C., consisting of pentane and amylene hexane and hexylene heptane and heptylene

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(2) 65°-70° C., (3) 94-97 C., Members of the acetylene and benzene series were absent.

Extended experiments with the portions distilling from 100° C. up to 300° C., and the solid hydrocarbon left above 300° C., showed them to be mixtures of saturated hydrocarbons and olefines. In the fractions distilling below 100° C., these two classes of bodies were in nearly equal proportions, but above that temperature the proportion of paraffin hydrocarbon to olefine became gradually larger as the molecular weight increased.

In cracking a heavy oil there are two factors that govern the course of the actions taking place, and these are temperature and pressure. The first loosens the groups of atoms that build up the complex molecule; the second to a great extent determines whether the action is a dissociation or a decomposition.

The temperature at which the dissociation takes place is above the boiling point of the heavy hydrocarbons, and if no pressure is employed the oil vaporises and the amount of alteration that takes place is small and depends on the local heating of the vapours as they are formed, but if pressure is used the necessary temperature for dissociation is reached, and by suiting the temperature and pressure to the particular mixture of heavy hydrocarbons being dealt with, the maximum of alteration with the minimum of decomposition can be attained. Directly the action commences to be be decomposition, gases are evolved, and carbon with heavy asphaltic bodies make their appearance in the residual liquid, while the volume of gas affords an index to the amount of decomposition taking place.

The more complex the original molecule the lower the temperature needed to loosen the bondage of the groups it contains, and therefore the

easier to prevent decomposition; hence Thorpe and Young, using a nearly uniform compound like paraffin, were able to dissociate it entirely at a temperature of between 300° C. and 400° C., and prevent decomposition by distilling and condensing under a pressure of 25 lb., but when we come to deal with a mixture of complex molecules, such as are found in Solar oil, the dissociation temperature of some is well above the decomposition temperature of other molecules, and the temperature at which it is best to carry on the conversion can be found by determining the temperature at which part of the oil just commences to decompose, i.e., gives off 10 or 12 cubic ft. of gas per gallon at atmospheric pressure, and then to regulate the pressure so as to prevent any gas being evolved.

With a Solar or other residual oil, what is wanted is a temperature round about 500° C., and a pressure that may run up to 1000 lb. or more if heavy oils are being treated. It is also clear that the heated hydrocarbons must be cooled down under pressure to prevent the chance of a decomposition temperature existing in the liquid and to prevent the escape of the more volatile products of the conversion as vapours.

It was this principle that was embodied in the apparatus which was patented by Sir Boverton Redwood and Sir James Dewar in 1889, and has been copied in the Burton process by which, at the present time, thousands of tons of heavy residual oils are being converted into lighter products by the Standard Oil Company. In both cases the form of apparatus is identical; large vessels or boilers are employed, and the pressure is restricted to 4 or 5 atmospheres, whilst the temperature is 400° C. to 500° C.

Burton's patent was granted on the grounds that by his process only hydrocarbons of the paraffin series were formed, whilst in all previous processes a mixture of the saturated and unsaturated series was produced, this idea being due to the fact that the bulk of the unsaturated hydrocarbons formed were naphthenes.

The inventor of another process obtains greater safety by heating the flowing oil in a coil of iron tube heated to tube heated to about the same temperature (450° C.) in a bath of molten lead at a pressure of 40 to 50 atmospheres, the oil then flowing to a second coil in a water condenser; this process differs from the previous ones by the pressure being kept sufficiently high to prevent any vaporisation. These processes may be taken to represent simple conversion, and the products found in the low boiling portions are chiefly paraffins, olefines, and naphthenes.

Α very interesting process for making "cracked" spirit is that devised by Mr. W. A. Hall, in which dissociation, decomposition, and recombination all play a part, as after vaporising the oil and passing the oil vapour at a rapid rate of flow through a great length of tube heated to about 600° C. under a pressure of 60 lb., he suddenly lowers the pressure by allowing the heated and decomposing oil vapours to pass into

a 12-in. column and then through dephlegmators, which cut out the heavier portions of the residue, the vapours and gases passing on into a condensing chamber, where they are compressed to 100 lb., and under this pressure go through the condensing coils. There seems to be an endothermic reaction taking place during the condensation by pressure, as a fall of temperature takes place where one would have expected a rise from the compression, and the liquid finally condensed contains not only gas in solution, but excessively volatile hydrocarbons evidently formed by the nascent gases attaching themselves to other molecules or polymerising. Such a spirit is far more complex than one formed by dissociation acting alone, as, besides the paraffins, olefines, and naphthenes, we also find aromatic hydrocarbons, acetylenes, and bodies like hemiterpene and terpenes.

During the past ten years several processes have been introduced in which steam or water has been introduced with the oil into the cracking ducts, the idea being that hydrogen from the water would affix itself to the heavy hydrocarbons and hydrogenate them into lighter hydrocarbons; to aid this action catalysts have been frequently used, nickel being the most popular.

The idea of the use of nickel as a catalyst is twenty-seven years old, as, in 1888, Ludwig Mond took an English patent, 12,608 of that year, in which he mentions the treatment of hydrocarbons, together with steam, by passing them through heated vessels containing fire-brick or iron oxide, and he states that if metallic nickel is used in place of the iron oxide, then only a moderate temperature is required.

About 1900, Sabatier and Senderens studied the action of nickel and other metallic catalysts on the hydrogenation of oils, and in the following years there were many more patents taken covering its use. Still later there were a large number of patents taken in America by Dr. Day, Ellis, Kayser, and others, dealing with the use of nickel as a catalyst.

Mond, Sabatier, and Senderens all recognised that such surface action as the nickel exercised took place only at temperatures below, at any rate, 300° C., but the more recent exploiters of the idea have drifted back to the temperatures one would use for cracking, not for hydrogenation.

Mr. Edgar A. Ashcroft has been doing some extremely interesting and highly suggestive work. Starting with the theory that the crude oil, as we obtain it from the well, represents a mixture in which the groups of atoms forming the molecule have, under the influence of temperature and pressure existing during the formation of the oil, arranged themselves as compounds in a proportion that has given a natural equilibrium, he suggests that if the crude oil be distilled so as to eliminate the lighter fractions and the residue be again subjected to the same temperature and pressure as that at which it was formed, a natural equilibrium will again be reached by the formation of a mixture akin to the original crude oil,

from which more light fractions can be distilled. In the same way, when coal is destructively distilled, the gas and tar represent a molecular arrangement which is in a state of natural equilibrium, so that by taking a middle fraction of the distillation of such tar, say creosote oil, and subjecting it to heat and pressure, tar, with its low boiling hydrocarbons, middle fractions, and pitch, should be again formed. That this is so is seen from the following experiment.

Two hundred c.c. of creosote oil, distilling between 240° C. and 350° C., were heated in an autoclave up to 490° C., which gave a pressure of 100 atmospheres; on allowing to cool down 180 c.c. of tar and 5 litres of very rich gas were found to have been formed. The tar on distillation gave :

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T is not only His Holiness the Pope who is servant of God's servants; the title well becomes all who are saving or safeguarding the health of the British Expeditionary Force. To read the medical and surgical history of past wars

the American Civil War, or the Crimea, or the Franco-German War-is more pain than pleasure. To read what our Army Medical Service is doing now-a Committee has just been appointed for the writing of this history-will be not the least of the pleasures of peace. We have a foretaste of it, in the article which was published in the daily papers last week, by "an Eye-Witness present with general headquarters." He says, to begin with, that a war such as this, with so much hardship and exposure, would have cost our nation, a few years ago, an outbreak of disease that would have decimated our forces. He goes on to say that the low sick-rate in the Army to-day is due, partly, to the diligent instruction given of late years to our men in the first principles of health. "In the main, however, it is due to the preventive measures adopted by the medical service." And these preventive measures are of two kinds: those which prevent infection from gaining access to our men, and those which strengthen our men to withstand infection.

The article is mostly concerned, and no wonder, with typhoid fever. Yet, if we think of single cases, not of masses of cases, the protective treatment against tetanus, surely, is not a less achievement than the protective treatment against

typhoid. Early in the war, the bad news came of many cases of tetanus; the heavily manured soil of France was full of tetanus; the very earth that our men were helping to defend was their enemy. It is a great blessing that a wounded man may indeed be safeguarded, with a dose of anti-tetanic serum, against this disease; and a great blessing that our men now are on soil which is fairly free from it.

But typhoid, after all, is the supreme test of the efficiency of an army medical service. We have learned of late years that the infection may be conveyed by flies, and by clouds of dust; we have learned also the danger of infection from mild, unsuspected cases, and from typhoidcarriers; we have left off thinking that typhoid cannot be spread without the help of a "polluted water supply." The present control of typhoid for our Army in France has been won by the bacteriologists; all honour to them :

Mobile bacteriological laboratories have been installed expressly for this purpose (the early detection of cases). Each laboratory consists of a motor-lorry fitted with a complete bacteriological equipment, and is in charge of a specially-trained officer, and an attendant of the Royal Army Medical Corps.

Moreover, it is the bacteriologists who discovered the protective treatment against the disease. On March 5 we learned what our Army owes to that treatment. Of fifty deaths from typhoid fever among our men on active service, forty-eight had occurred among the non-protected, one in a man protected, and one in a man partly protected. Nobody in his proper senses doubt that Nature finds it easier to kill the nonprotected than to kill the protected.


It must not be forgotten that by far the most potent weapon in our armoury against typhoid fever has been forged by pathologists, before the war. Inoculation is the surest defence and to its extensive use must chiefly be attributed the low incidence of this terrible disease in the British Army.

But the whole article ought to be read carefully, not in fragments.

Doubtless, when the hot weather comes, the work of safeguarding the Army's health will be no less arduous than it is now. For the present, let us be thankful for the splendid services rendered by men of science to our defenders, through all the bitter hardship and perils of the past nine months. STEPHEN PAGET.



THE HE use of asphyxiating gases by the Germans in forcing back the French lines to the north of Ypres has given rise to much conjecture as to the nature of the gases employed, and in a long article in a Sunday paper it is surmised that the gas used was carbon monoxide. The only founda

tion that can exist for such an opinion is that

carbon monoxide is one of the most virulent gaseous poisons known, and that less than 1 per cent. in air rapidly proves fatal, but inasmuch as all the explosives in general use produce it in large quantities, the smokeless powders in use by

England, France, and Germany, giving approximately 50 per cent. of the permanent gases formed as carbon monoxide, it is hard to believe that the enormous volume produced by firing the charge in the gun should have no deleterious effect on those using it, whilst the much smaller quantity given on the bursting of the shell should asphyxiate the enemy. The fact is, that carbon monoxide is slightly lighter than air, and when driven out by the explosion in a heated condition diffuses upwards so rapidly that scarcely a trace can be found at the breathing level, but when evolved underground in a confined space many accidents have been caused by its poisonous properties.

Moreover, carbon monoxide is in no sense of the word an asphyxiant, and one of its greatest dangers lies in the fact that air containing poisonous amount can be readily breathed.

Later reports received on Monday and Tuesday make it evident that it was a true asphyxiant, such as sulphur dioxide, chlorine, or a mixture of the two that was employed, and that the fumes generated in front of the German trenches were borne down by a northerly wind upon the Allies. Some descriptions speak of the burning of some substance which gave a yellowish smoke and gases; others that the gases were contained in steel cylinders, the gases being conducted by hosepipes some little distance in front of the trenches, whilst the men manipulating the cylinders wore divers' helmets, and the first German troops to charge over the gassed area wore smoke helmets or respirators. It is further probable that some shells containing a liquid giving gases of an asphyxiating character were also employed.

It seems to be clear from various descriptions that the gases floated close to the ground for a considerable distance, producing an effect of asphyxiation, which was felt as far as the Allies' second lines.

Both sulphur dioxide and chlorine would have produced the effects described, and the cylinders spoken of might have contained these gases in a liquefied form, whilst it is probable that shells used for asphyxiating purposes would be charged with chloride of sulphur which would itself decompose in moist air or in contact with water into sulphur dioxide, hydrochloric acid, and sulphur, or, if fired by the bursting of the shell, would give sulphur dioxide and chlorine.

Both sulphur dioxide and chlorine satisfy the requirements of being more than double the weight of air, and so might remain near the ground, diffusion being only slow, but it is difficult to understand how sufficient quantities of either gas were produced to render the air irrespirable at the distance of the Allies' lines from the German trenches.


BOTH zoologists and geologists lament the on April 16 of Mr. Richard Lydekker, who had been for more than thirty years one of the most active workers in the natural history sciences. Born in 1849, of Dutch descent, he was educated at Cambridge, where he graduated

in 1871, and was placed second in the first class of the Natural Science Tripos. Joining the Geological Survey of India in 1874, he began his scientific career in the mountains of Kashmir, of which he made a successful pioneer geological exploration. While there his opportunities for sport continued to foster his interest in zoology, and he soon acquired a good knowledge of the mammals and birds of the country. The great collection of Tertiary mammalian remains in the Indian Museum at Calcutta then attracted his attention, and he began a systematic study of these fossils, which he described in the Palaeontologia Indica.

With little material for comparison in India, and needing the corresponding collections in the British Museum for reference, Mr. Lydekker soon recognised the necessity of returning to London if his work was to be exhaustive. He accordingly retired from the Indian Survey in 1882, had the fossils from Calcutta sent in instalments to London, and by 1887 had completed the fine series of volumes describing not only the Siwalik Vertebrata, but also the pre-Tertiary Vertebrata of India. At the same time, between 1885 and 1887, Mr. Lydekker prepared for the British Museum a catalogue of the fossil mammals in the department of geology (in five parts), which was followed by similar catalogues of the fossil reptiles and amphibians (four parts, 1888-90), and fossil birds (one part, 1891). Though presenting only a somewhat hasty and superficial view of the subject, these catalogues were at the time of real utility; and they are noteworthy as the first systematic attempt to correlate the European with the more recently discovered American fossils.

In 1893, and again in 1894, Mr. Lydekker visited the Argentine Republic and spent some months in studying the wonderful collection of fossil vertebrates in the La Plata Museum. His work was published in two handsomely illustrated volumes ("Anales del Museo de La Plata," tomos II., III.), and gave the first satisfactory account of several of the peculiar extinct vertebrates of South America. His descriptions of ancestral Cetacea from the Tertiary, and Dinosaurian remains from the Cretaceous, formations are especially valuable. The visits to South America led Mr. Lydekker to appreciate more thoroughly the need for considering the evidence of fossils when dealing with questions of geographical distribution, and in 1896 he published a "Geographical History of Mammals," which is in many respects his most original and important work.

While occupied with purely scientific research, Mr. Lydekker did not overlook the needs of ordinary students, amateurs, and sportsmen, and during his later years most of his numerous writings were adapted for their use. So long ago as 1889 he contributed the volume on vertebrates to the third edition of Nicholson's "Manual of Palæontology," and in 1891 he co-operated with Sir William Flower in "An Introduction to the Study of Mammals.' Between 1893 and 1896 he also edited the "Royal Natural History," and

wrote the section on vertebrata. Work of this kind was facilitated by his occupation at the British Museum in arranging the exhibited collections of mammals and reptiles in the department of zoology, where he was employed from 1896 until the time of his death. He not only arranged the collections in an admirable manner, but also prepared several valuable guide-books. His last work was a catalogue of Ungulate mammals in the British Museum, of which three parts were published, and the fourth, completing the Artiodactyla, was left by him nearly ready for issue.

Mr. Lydekker was elected a Fellow of the Royal Society in 1894, and was awarded the Lyell Medal by the Geological Society in 1902.

DR. W. J. SELL, F.R.S.

WILLIAM JAMES SELL, university lecturer and senior demonstrator in chemistry at the University of Cambridge, died at Cambridge after a long illness on March 7. He was born at Cambridge in 1847, and for more than fifty years was connected with the chemical laboratories there, and contributed in no small degree to their development and success. He was barely fifteen when, on the recommendation of the master of the elementary school which he attended, he was employed at the chemical laboratory of St. John's College, at that time the only one in the University open to undergraduates. Here he learnt elementary analysis and the use of apparatus, heard the professor's lectures, and saw his experiments. He made good use of his opportunities, and soon made himself an efficient assistant. In 1865, when the Jacksonian professor of natural philosophy removed his apparatus into a new building, the room vacated by him was united with that of the professor of chemistry, and a room built above them for a students' laboratory, the first step taken by the University, in its corporate capacity as distinct from the colleges, to provide experimental training for its students. Here Sell was appointed attendant, and had charge of the apparatus, and not only assisted the professor in the experiments at his lectures, which at that time embraced physics as well as chemistry proper, but was much in demand to help the students, whose notions of making experiments were often crude. The laboratory was a poor place at best in comparison with modern laboratories, but it grew and became filled with students, to which result Sell's help contributed not a little.

In 1870 Sell married, and soon after entered Christ's College and matriculated in the University. He had acquired a good knowledge of chemistry, and of some other, branches of natural science, and knew a little of modern languages, but no degree could be obtained at Cambridge without some acquaintance with Latin and Greek, and he had not learnt either. It was a formidable task to begin now, but he faced it with his usual quiet determination, studying Latin and Greek at all times when his duties at the labora

tory permitted, passed the examination in both languages, and was then able to take the Natural Sciences Tripos for his B.A. degree. In this he obtained a first class in honours for chemistry in 1876. This success brought him private pupils, and therewith an increased income, very necessary for him because University posts were all meagrely paid; at the same time he took a demonstratorship instead of remaining assistant to the professor. A short time afterwards he succeeded to the place of principal demonstrator.

Although Sell's position in the University, thenceforward to the end of his life, was that of a demonstrator, it must not be supposed that his public teaching was confined to what is usually known as demonstrating, which is mainly done. by the junior members of the staff. On the contrary, inasmuch as chemical science was constantly expanding and learners increasing in number, the lectures had to be more specialised and the classes subdivided. The University had not the means to multiply the professors, and so the staff of the laboratory had to meet the demand for more instruction as best they could amongst themselves. In this Sell was most serviceable. He shirked nothing so that the teaching might, so far as lay in his power, keep pace with the growth of knowledge, and for many years was in reality an effective professor, though in name. only demonstrator. He was never what is called a brilliant lecturer, but was a sound teacher, who gained the confidence of his hearers, and attracted them by his painstaking sincerity and willingness to help anyone in difficulty.

Sell had been elected a Fellow of the Royal Society of London in 1900, and took the degree of Sc. D. at Cambridge in 1906. An attempt was made to get him promoted to the rank of reader in chemistry. The University has full power to do that, and there were similar applications in connection with other branches of learning, and Sell's friends thought that his distinction as a chemist, and his long and faithful devotion to the service of the University, gave him a claim to promotion at that time before any other aspirant to the same rank. The appointment of readers, however, does not rest with the University at large, but with a board composed of representatives of the various departments of knowledge, literary as well as scientific-in fact, with a body of specialists chosen as such. As always happens in such cases, every member of the board thinks that his foremost duty is to see that his own particular subject of study gets its share of money and places, and magnifies it accordingly, so that the board scarcely ever pulls together for the general advantage, still less to do justice to an individual. No readership was created at that time, and all the recognition Sell got was his appointment to a University lectureship with a stipend of 50l. a year.

In his younger days, when it was as much as he could do to maintain his family, he could scarcely spare time for original investigations; but later, when the laboratory was grown up and needed

less nursing, he was able to show that he had the capacity for successful research and the will to advance knowledge himself, quite as much as to put others in the way of doing it. He will be best known by his work on pyridine derivatives, to which he was led by previous studies of citrazinic acid. These were the subjects of a large number of communications to the Chemical Society from 1892 onwards. In some of these researches he was assisted by one or other of the advanced students in the laboratory, while in other cases he worked alone. Without going into details, it may be mentioned that from pyridine he obtained eight distinct chloro-derivatives, and from pyridine hydrochloride, in addition, some remarkable dipyridyl compounds. Moreover, he did not fail to demonstrate the chemical constitution of most of the new compounds he discovered. Other subjects of interest investigated by him were the salts of a base containing chromium and urea, and colloid solutions of phosphates. All he did bore the stamp of careful accuracy, and he impressed on his pupils the necessity for sparing no pains to ensure this, if any real advance of knowledge were to be made.

He was so unassuming that only those who had known him long found how much was hidden under that modest behaviour. It really meant that he wished always to do what was right, whether convenient or inconvenient, and to believe other people to be as good as himself.


DR. H. KAMERLINGH ONNES, professor of experimental physics in the University of Leyden, has been awarded the Franklin medal of the Franklin Institute of Philadelphia.

In spite of the war, the usual Dutch biennial congress of Science and Medicine was held this year, at Amsterdam, the first day being April 8. In 1917 the congress will meet at the Hague.

DR. J. ALEXANDER MURRAY has been appointed general superintendent of the Imperial Cancer Research Fund, and director of the laboratories, in succession to Dr. E. F. Bashford.

THE Meteorological Office announces that Mr. J. E. Cullum retires from the post of superintendent of the land, and that Mr. L. H. G. Dines has been appointed Valencia Observatory, Cahirciveen, Co. Kerry, Ireto succeed him, as from May 1. Mr. A. H. R. Goldie has been promoted senior professional assistant in succession to Mr. Dines at the observatory at Eskdalemuir.

Ar the beginning of the war the Meteorological Office ceased the issue of weather charts to the newspapers. Announcement is now made that from May 1 the weather forecasts from the Meteorological Office for the several districts of the British Isles will not be available for publication. The only forecasts issued will be in what is known as the harvest weather forecast service. These are entirely local in character, and are telegraphed to agriculturists upon payment of the cost of the telegrams.

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