502 teeth, playtime, and leisure. Some standard method of testing the hearing of children is desirable. Reports from other countries show that 12 per cent. to 20 per cent. of An school children may be defective in their hearing. examination of the teeth of 10,500 English and Scotch boys and girls of an average age of twelve years in poor law schools, workhouses, and reformatories showed only 14 per cent. of these children with teeth free from decay. The children in our public elementary schools are in a much more neglected state than the poor-law children. committee thinks that daily cleansing of teeth should be enforced by parents and teachers, and that dentists employed by school authorities should make systematic examination of teeth. The active and constructive work on the part of children should be largely substituted for ordinary class-teaching. To make this possible, smaller classes, trained teachers, and sympathetic inspectors are necessary. Supplementary reports of subcommittees were presented by Prof. R. A. Gregory on arithmetic and mensuration, by Mr. R. H. Adie on naturestudy, and by Mr. George Fletcher on domestic work. There was an eager and universal request for copies of the full text of these reports, and the printed supply proved very unequal to the demand. The committee of the section proposed to arrange for further reprints. Prof. Green saiu that primary teachers needed training to use the freedom now given them, and needed also the opportunity of a higher professional course at the universities for those desirous of promotion. Mr. Cyril Jackson admitted the Sir Lauder Brunton spoke on physical education, and difficulties of large classes, Mr. T. P. Sykes emphasised showed that mind development was brain development. the need for freedom to experiment, and Dr. Traill the The teaching of hygiene might begin with the washing importance of training teachers before trying to He urged the medical inspection of and dressing of dolls. reforms through the schools. schools, and brought to the notice of the section the National League of Physical Education and Improvement. His lecture was supported by a most welcome and generous distribution of pamphlets sent by that league, and his display of lantern-slides in the adjacent room when the botanists adjourned for lunch allowed of the presentation of evidence to a section which does not always find it easy to get at the facts which underlie opinions. Dr. Ethel Williams gave careful estimates of the time, cost, and usefulness of medical inspection. In Newcastle, with 45,000 children on the books, three officers could inspect each child thrice in its school life at a cost of about 2000l. per annum, equivalent to a farthing rate. For the whole country 200,000l. would give similar inspection of children, with supervision of epidemics and of school buildings. Prof. Sadler pointed to the crux of the on medical officers' difficulty in getting parents to act reports, and Mr. Ernest Gray spoke of the attitude of suspicion in the working classes. Major Salmon spoke of the Swedish system of gymnastics as developed in Denmark. To keep the air clean for breathing exercises a damp felt or sacking is passed over the floors before every lesson. move in one's Mr. A. Burrell said that freedom to clothes and a sense of cleanliness were the bases of true hygiene. The rightly dressed, clean child, and the wellventilated class-room were the best lessons. Organised games had been approved, but playing centres had not yet been provided. A medico-ethical training was necessary for the teacher who was to stand hour by hour before weak sight, incipient deafness, and malnutrition. There should be a standard of health in training colleges analogous to that demanded by the Army and Navy. Mrs. J. R. Macdonald showed how all schemes for the education of wage-earners of school age were bound up with social and economic questions. She urged a better enforcement of the Employment of Children Act, 1903. Mr. Hugh O. Meredith described the Workers' Educational Association-an effort to organise the higher education of working men by means of collegiate life in local guilds associated with the University Extension movement. Arnold S. Rowntree explained how similar ends achieved by the adult schools meeting on Sunday mornings. Mr. were The discussion in Section I on the physiological value of rest might almost have been called a joint meeting, considering its interest for those attending Section L. Dr. Acland found that sleep was necessary for the growth of the brain and nervous system, and that many schools had not secured sufficient sleep either for younger boys or for those Mental and bodily health canolder boys who needed it. not be severed, and muscular exertion is not a remedy for brain fatigue. Dr. Bevan Lewis correlated brain-fag with The minimum of sleep for growing muscular fatigue. children was not defined, but no one advocated less than nine hours. Laboratory investigation into the general laws of fatigue is needed in the opinion of Dr. W. H. R. Rivers.. Dr. Macdougall suggested that early morning sunlight should be shut out of a child's room. Sir Philip Magnus presented the report upon the course of Experimental, Observational, and Practical Studies most Suitable for Elementary Schools. The committee asks that rust, In the discussion on School Training for the Home Duties of Women, Prof. A. Smithells said that at presen! home training reveals the methods of superstition, ignorance, prejudice, and folly. Nor does a formal course on the oxides of nitrogen and chlorides of phosphorus always produce a scientific attitude of mind in a household where ovens will not heat and meat will not keep. A schoolmistress with a scientific degree may fail to understand the hot-water system, the gas meter, or the filter. There is a more excellent way, and it is possible to develop a science of the household free from pedantry and free from empiricism in that vast undeveloped intellectual region The disconnected with the domestic work of women. cussion was continued by Prof. Armstrong, Prof. Millicent Mackenzie, and others. The morning of Monday, August 6, was reserved for those public- and secondary-school questions relating to the Balance of Subjects in the Curriculum, the perennial interest Карра and by the in which has lately been revived by Papers contributed by the Hon. and Upton Letters.' Rev. E. Lyttelton and by Mr. A. C. Benson were read in the absence of the authors. The possible omission of Latin in the preparatory school seems to have come within the range of discussion; at any rate, precedence for French seems agreed upon. Mr. T. E. Page proposed a committee to draw up a scheme of general study, to indicate the method and purpose of teaching the various subjects, and to show at what stage specialisation should be allowed. Mr. G. Gidley Robinson spoke of the preparatory-school master as not a free agent, scholarships being the root of the mischief. Mr. Arthur Rowntree assumed that training for power of work and service should be the prime object of education, and asked for an unburdening of the curri culum to allow of individuality in leisure hours. Scientific Method in the Study of School Teaching was Progress has been described by Prof. J. J. Findlay. hindered by those earlier advocates of training who treated education merely as applied logic and ethics, but progress may be expected from experimental psychology and genetit psychology or child study. The popular interest in educa tion leads to the ready adoption of opinions rather than the encouragement of prolonged investigations; but results in methods of school teaching can only be secured br observation of children. Educational experiments require the cooperation of several teachers for several years withost The native speech centre is a special hindrance, and the translation habit, although the path of least discomfort, is really a bar to progress. The rate of progress depends upon the intensity of the learner's absorption during the early stage. Inquiry into cases of aphasia among bilingual people may be expected to throw some light upon the nature of brain centres for foreign speech. The attempt to establish two foreign languages at the same time should not be made; each tends to inhibit the other. Latin, however, taken on a translation method does not appreciably interfere. Progress is hindered by the incapacity of some scholars to perceive new sounds. Mr. The discussion on the Examination and Inspection of Schools was started by Prof. Armstrong, who asserted the need for freedom to develop individuality. The ideal system would be for the schools to examine themselves with the aid occasionally of competent assessors. W. M. Heller spoke on the constructive work of an inspector of schools. The transition from payment by results to inspection was accompanied for some years by a diminution in the proficiency of pupils. An inspector should possess successful teaching experience in both primary and secondary schools, if possible with the wider outlook of a headmaster. It takes time to know a large number of schools and teachers, and first impressions are sometimes wrong; hence an inspector should be left for several years in the same district. An inspector has a magnificent field for scientific research; he can watch, foster, and institute educational experiments of all kinds. The Rev. E. C. Owen doubted whether the inferior teacher well inspected was an improvement on the good teacher uninspected. Training would never eliminate mediocrity. If practical experience in teaching were made a sine qua non for administrative posts, this would attract good men to educational work. A joint meeting was held with Sections A and G to discuss the Teaching of Mechanics by Experiment. Mr. C. E. Ashford spoke of the results obtained at Dartmouth by the cooperation of schoolmaster and engineer, and the use of real machinery instead of scientific toys. The science master who plays with laboratory toys is apt to be too academic, and the technical schools are too rule-of-thumb, lacking the rigorous mathematician and trained educationist; but the finest of laboratory toys were the delightful trolleys and vibrating springs shown by the lecturer and used by his pupils for measuring velocity, acceleration, and momentum. Those who attended Section L greatly enjoyed Prof. Sadler's chairmanship, "serious and sunny.' "His summing up at the close of each day's discussion pointed through primitive chaos to the spirit of search, the growing desire for educational unity, and the fading away of narrow aims. HUGH RICHARDSON. INTERNATIONAL TESTING CONGRESS. IN NATURE of September 6 (p. 471) brief reference was made to the opening of the International Testing Congress at Brussels on September 3. The work of the sections began on September 4, and was continued on September 5 and 6. The amount of work to be dealt with was so considerable that three sections were formed, A dealing with metals, B with building stone and cement, and C with other materials. Altogether there were twentyseven reports of committees and forty-five original papers, the greater portion of which were submitted to the section on metals. Mr. J. Magery (Namur) presided over this section, and he was supported by honorary presidents representing the various nationalities present, and including Messrs. Wedding (Berlin), Brough (London), Saladin (France), Hackstroh (Holland), Chernoff (Russia), Brinell (Sweden), Popper (Austria), and Tonello (Spain). following are brief notes on the various reports presented :Mr. A. Rieppel (Nuremberg) reported on the introduction of standard specifications in various countries; Mr. W. Ast (Vienna) reported on methods for inspecting and testing in order to ensure uniformity in iron and steel; Mr. R. Krohn (Danzig) reported that it was not feasible to establish standard welding tests. Prof. E. Heyn (Berlin), reporting on the value of etching malleable iron The for the investigation of structure, showed that examination by the unaided eye gave valuable information as to the character of quenched high-carbon steel. Prof. N. Belelubsky (St. Petersburg) reported on the unification of methods of testing, and submitted a series of proposals. Prof. H. M. Howe and Mr. A. Sauveur submitted proposals for the uniform nomenclature of iron and steel. Dr. R. Moldenke (New York) reported on the establishment of standard methods of testing cast-iron and finished castings. He noted that the American and German specifications differ but slightly, and could easily be made identical. Mr. E. Sauvage (Paris) submitted a report on impact tests on notched bars, and there was an animated discussion as to the value of this method of testing, opinions being equally divided as to the desirability or not of recommending it in specifications. The Brinell hardness test, which was reported on by Mr. J. A. Brinell and Mr. G. Dillner (Stockholm), was also keenly discussed, the general opinion being that, with the view of placing information on record, tensile tests of metals should, when possible, be supplemented by tests by the Brinell method. Mr. W. Ast (Vienna) submitted a report on international researches in the macroscopic examination of iron. The etching test is recommended for preliminary examination. Lastly, Mr. F. Osmond and Mr. G. Cartaud (Paris) submitted an interesting report on the progress of metallography since the Budapest congress of 1901. The second section, dealing with cements, was under the presidency of Mr. Levie (Charleroi). The subjects dis cussed included the determination of the adhesive force of hydraulic cement, the determination of the weight of a litre of cement, and the behaviour of cement in sea-water. It was decided to appoint a committee to inquire into reinforced concrete. The third section, under the presidency of Mr. E. Roussel (Malines), devoted attention to tests of paints, linseed oil, wood, bitumen, asphalt, and india-rubber. The congress concluded with a lecture by Prof. H. Le Chatelier (Paris) on the practical applications of metallography. An interesting feature of the congress was a small laboratory installed to illustrate modern methods of testing, under the direction of Prof. Le Chatelier, Mr. Guillet (Paris), and Prince Gagarine (St. Petersburg). It was decided that the next congress should be held in 1909 in Copenhagen under the presidency of Mr. A. Foss, president of the Society of Danish Engineers. CAMPAIGN. THE ANTI-TUBERCULOSIS THE Hague, preparing to receive the great Peace Congress of 1907, which is to discuss questions of peace and disarmament, recently entertained delegates from the chief European and American States to the fifth International Conference on Tuberculosis. At this conference questions of increased armaments were discussed, with the view of waging a more effective war against this great evil. The great interest taken all over the world in the proceedings of the conference testifies to the awakening of mankind to the necessity of making further and greater efforts in order to reduce the ravages of tubercular infection to a minimum. At the present time the campaign against tuberculosis is being carried on with greater energy than at any previous period in medical history. Since Koch's discovery of the tubercle bacillus in 1882, and the publication of his exhaustive researches arising therefrom, it has been known to medical men that tuberculosis is as much a preventable disease as plague or cholera. Nevertheless, the public in England have remained until very recently apathetic and apparently indifferent to the fact that untold misery and sixty thousand actual deaths occur annually from a disease which can and ought to be eradicated. At last we are waking from our lethargy. This change has been gradually induced by the insistent pressure of medical opinion, aided largely by the King's active sympathy and interest. More lately Prof. Wright's great work on opsonins has given fresh hope and energy to many who were becoming jaded in an apparently hopeless conflict. 504 Since 1851 statistics show a steady decline in the mortality of tuberculosis, and for this the principles of general sanitation have been chiefly responsible. We may expect in the future that this improvement will be maintained by the continued prevention of overcrowding, the enforcement of good ventilation, improvement of insanitary areas, more effective drainage, better cleansing of streets, and the more stringent supervision of meat, cowsheds, dairies, &c.; but more rapid progress may be made and eventual extinction of the disease attained if more direct measures are employed in an intelligent and comprehensive manner. The Of more direct measures, hospitals for consumption have at Midhurst, perhaps the most perfect of its kind in the Another philanthropic body, under the presidency of Hitherto sanatorium treatment has mainly consisted of fresh air, rest in bed, full diet, and graduated exercise under constant medical supervision. Such a life is not a sanatorium very healthy moral existence; it produces the " habit," which renders one who has acquired it morally unfit, as he is already physically, for the more strenuous In order to life to which he must sooner or later return. counteract the emasculating influence of sanatorium life as hitherto pursued, to reduce the cost of maintenance, and in order to provide work for patients who would otherwise lead an indolent and purposeless life, various schemes have been proposed. The Open-air League intends to found farm colonies in connection with its sanatoria where patients cured, but as yet unfit to return home, may occupy themselves in farming, in the cultivation of vegetables, and other similar light occupations. An intermediate stage is thus created during which the patient is braced up physically and morally, minimum. and his tendency to relapse reduced Hospitals and sanatoria, however, under their rules exclude to a cases of advanced tuberculosis. Such cases under hospital In (2) Inquiry by a medical man or nurse into the history of the illness, the home conditions, the economic condition of the family, the suitability of the accommodation for home treatment. (3) Arrangements for providing medical treatment and risk of infection. nursing of patients that could be treated at home without (4) Dispensing of medicines and disinfectants. (5) Selection of cases suitable for hospital treatment. The type of dispensary which might well be copied by other cities is the Royal Victoria Dispensary, founded eighteen years ago by Dr. R. W. Philip in Edinburgh. The excellent work done by this pioneer institution has been of incalculable benefit to the community. By these means the campaign is carried into the very homes of the patients, and an attempt is made to limit at its source the constant stream of more or less advanced cases of tuberculosis which appear daily in the out-patient departments of our hospitals. The cost of such dispensaries is not great; Dr. Philip estimates it at 500l. to 1000l. per annum for a city o 300,000 inhabitants. It might be paid out of the rates and the dispensaries, for administrative purposes, should be under the control of the medical officer of health Pulmonary tuberculosis has been recognised in Scotland by the Local Government Board as an infectious diseas within the meaning of the Public Health Act (Scotland 1897; consequently the obligations of the local authority with regard to infectious disease are extended to phthisis. and much more efficient control is established. Under the Infectious Diseases Act (1889) the Loral Government Board can invest local authorities with similar In Sheffield these powers have been obtained in powers. a modified form, and in Manchester and some other localties notification of tuberculosis has been tried with success Surely the time has now arrived when the power possible under the Infectious Diseases Act should be more generally employed. A system of voluntary notification has been inaugurated in Manchester; this was at first limited to public institutions, but in 1900 medical men were invited to notify the cases occurring in their private practice. The system has worked well, and has been of immense benefit in affording opportunities for visiting the homes of the patients and instructing them in the principles of disinfertion, ventilation, and the proper disposal of sputa, &c. cannot be doubted that some system of notification ivoluntary or compulsory) is imperative if efficient control to be obtained. It is not contended that notification by itself has any administrative value, but if efficiently followed by adequate preventive measures it would alter the whole aspect of affairs; on the other hand, application of the provisions of the Public Health Act to tuberculosis impossible unless some system of notification is employed Many new cases of infection arise from ignorance of the infectivity of tuberculosis, and from an absence of an knowledge as to how best to live without spreading irl tion. To combat this local authorities have distribu leaflets conveying simple instructions for the everyday li of tuberculous persons, and various philanthropic bod (e.g. the Open-air League) have this education of the pe as one of their chief objects. Brighton, however, under the able leadership of få Newsholme, has struck out a new line. The vacant wards of the hospital are utilised for the education of consumptives. Patients living at home are admitted to the hospital for short periods (four to six weeks), during which time they are instructed as to how they should live and in all the precautions and preventive measures they should practise on returning to their homes. In this way a constant stream of enlightened information is continually disseminated among the most ignorant. Some other towns are following this excellent example. Although it has been shown that much time, money, and energy are being expended by various public and private bodies in the effort to throw a net over the whole tuberculous population, yet it must be confessed there remain many gaps which must be filled up if success is to be attained in our war against consumption. Proper organisation and coordination of effort are needed. A well-thoughtout scheme must be put in action throughout the country and controlled by some central authority. This duty falls naturally to the Local Government Board, and is it too much to expect that a "tuberculosis committee of that board may be appointed the chief duty of which should be the control and direction of the isolated efforts now being made in various parts of the country? By this means greater efficiency and better results would accrue at a proportionately smaller cost. R. FIELDING-OULD. ATMOSPHERIC ELECTRICITY IN ALGERIA. IN the Revue générale des Sciences of May 30, M. Ch. Nordmann gives an account of the phenomena of atmospheric electricity, and of one or two of the latest theories on the subject, and also describes some recent observations made by himself in Algeria. Atmospheric electricity is now so large a subject that the essay naturally covers only a part of the ground, and does not go into many details. It shows, however, the clearness and lightness of touch one expects from our neighbours across the Channel. In a few points perhaps its conclusions are a little precipitate, but it contains some shrewd criticisms of other people's theories. The paper contains copies of some interesting electrograms, mostly obtained by the author in August and September, 1905, at Philippeville, on the Southern coast of the Mediterranean. M. Nordmann first points out that the normal potential gradient in the atmosphere may arise from a negative charge on the earth, or a positive charge in the air, or from the two combined. He regards the presence of an excess of positive electrification in the air as proved by the fall in the potential gradient with increasing height observed in balloon ascents. He refers to Elster and Geitel as having discovered that any charged body, however well insulated, loses its charge in ordinary atmospheric air. Historically this is hardly complete, as Elster and Geitel merely confirmed what Linss had discovered many years before. Elster and Geitel have, of course, added enormously to our knowledge of the subject, and they gave it much greater precision, besides bringing it into line with recent laboratory research. Passing to the diurnal variation in the potential gradient, P. 445, M. Nordmann refers to the double period with maxima about 8 a.m. and 8 p.m. as having been regarded until recently as universal. He next refers to observations on mountains, especially those on the Sonnblick, as showing that at high levels the afternoon minimum disappears, the diurnal variation becoming simple, and mentions Chauveau as having established the existence of the same phenomenon on the Eiffel Tower. In both cases the observations show rather a reduced prominence in the afternoon minimum than its total absence, and on p. 447 Nordmann somewhat qualifies his earlier remarks. His own observations at Philippeville supply a very interesting example of a simple period. Observing on an eminence 160 metres high, immediately adjacent to the sea, he obtained as the mean from the quietest days of his stay (the number of which is not stated) a diurnal variation with a minimum from 4 a.m. to 5 a.m., and a maximum about 5 p.m. The value was above the mean from 11 a.m. to to p.m., and below from 11 p.m. to 10 a.m. During the day the wind blew straight from the sea, and during the night from the land. The results are so unusual, and if confirmed so suggestive, that an extension of the observations over a much longer period is desirable. Until that is done, one cannot feel sure that the results are fairly representative, even of the particular season of the year when they were observed. Among the electrograms reproduced is one showing the effects of a sirocco from the desert. The large and sudden changes of potential, the curves going off the sheet both in the positive and negative directions, are similar to those met with in England during thunder or heavy rain. Other curves of interest are those showing the changes of the potential and of the positive ionisation of the air at Philippeville during the total eclipse of the sun on August 30, 1905. Between the times of the first and last contacts the potential was slightly above its mean for the time of the day, and the ionisation fell decidedly as totality approached. The maximum in the one curve and the minimum in the other occurred fortyfive minutes after totality. In his criticisms of theories by Elster and Geitel and Ebert the author points out that at Philippeville the potential was below, not above, its mean when the wind blew off the land, and that the barometric pressure showed the ordinary double period. In discussing some theoretical views of his own, he refers to a difficulty in that "en passant de l'été à l'hiver la diminution du rayonnement solaire s'accompagne d'un abaissement du champ, passant du jour à la nuit elle coincide, au contraire, avec une augmentation." This is rather puzzling in view of the author's perfectly correct statement, p. 446, that the potential is highest in winter. C. CHREE. UNIVERSITY AND EDUCATIONAL INTELLIGENCE. en THE University of Greifswald has received a legacy of 60,000 marks under the will of the late Dr. Milschewsky, who died recently in Loburg. PROF. MORRIS TRAVERS, F.R.S., professor of chemistry at the University College, Bristol, has been appointed director of the Indian Institute of Science which is to be established in Bangalore. ACCORDING to the Chemiker Zeitung, the authorities of the Zürich University have decided to increase considerably the University lecture and laboratory fees chargeable to foreigners, with the idea of lessening to some extent the present high percentage of foreigners who attend. IN the columns of the Chemiker Zeitung for last week we read that the Grecian Government recently received from St. Petersburg a legacy of about eight million roubles, or 1 millions sterling, which was left in the beginning of the last century by a rich Grecian merchant, of the name of Dombolis, with the condition that after the lapse of a definite time a second Grecian university should be built in Corfu out of the capital and interest, and be called the Kapodistrias University. THE fees for the examinations of the German technical high schools have been fixed on the following scale :--for the preliminary diploma examination, 60 marks for naturalised Germans, 120 marks for foreigners; for the diploma examination, 120 marks for Germans and 240 marks for foreigners; for the doctor of engineering examination, 240 marks, of which the first half is to be paid when the examination thesis is handed in, and the remainder before the oral examination is taken. THE university buildings of Groningen were almost completely destroyed by fire on August 30. The fire is supposed to have been caused by careless use of benzine or methylated spirits on the part of workmen. The natural history museum and the chemical and pharmaceutical laboratories were entirely destroyed, while the hygienic and physiological laboratories saved. The university buildings, which, strangely enough, were not insured, were erected in 1846-1852. An emergency committee has made arrangements for the lectures and classes of the coming session to be begun as usual. The University has approximately five hundred students. were THE prospectus of the Borough Polytechnic Institute for the session 1906-7 contains abundant proof that the educa 506 tional needs of the young men and women of South London IN the opening pages of the new calendar of the Uni- ments. A COMPREHENSIVE resolution referring to education was adopted last week at the Trade Union Congress at Liverpool. Among the points accepted by the congress as essential to a sound educational system are the following:-(1) scientific physical education with medical inspection and records of the physical development of all children attending State schools, and skilled medical attendance for any child requiring same; (2) a national system of education under full popular control, free and secular, from the primary school to the university; (3) secondary and technical education to be an essential part of every child's education, and to be secured by such an extension of the scholarship system as will place a maintenance scholarship within the reach of every child, and thus make it possible for all children to be full-time day pupils up to the age of sixteen; (4) the best intellectual and technical training to be provided for the teachers of the children; (5) the cost of education to be met by grants from the Imperial Exchequer, and by the restoration of misappropriated educational endow ments. SOCIETIES AND ACADEMIES. 66 Royal Society, June 28.- Researches on Explosives." Part iv. By Sir A. Noble, Bart., K.C.B., F.R.S. Researches on Explosives" the In part iii. of his author gave the results of a very extensive series of experiments on certain explosives, which were, first, the cordite of the Service, known as Mark I.; second, the modified cordite, known as M.D.; and third, the nitrocellulose, known as Rottweil R.R. The experiments made extended, for all the above explosives, from densities of 0.05 to 0.45 or 0.50, and pressures of from 2.75 tons per square inch (419 atmospheres) to pressures of 60 tons per square inch (9145 atmospheres). In the present paper full details are given of three other explosives, and comparisons are made between them and the explosives which have been so much experimented with in this country. If reference be made to the tables, which cannot be given in this abstract, it will be seen how wide are the differences between the explosives, not only in the absolute volumes of the several gases, but in the variations with reference to the densities at which they were fired. Thus, for example, comparing Norwegian 165 and Italian ballistites, while in the former the carbon monoxide commences at the density 0-05, with a percentage volume of 38.5, falling at a density of 0.45 to 22 per cent., the carbon dioxide commences with 13.3 per cent., rising rapidly to In the latter explosive the CO commences 31 per cent. at 20.5 per cent., and falls slowly to 15 per cent., while the CO2 commences a little above 26 per cent., rising also comparatively slowly to nearly 34 per cent. But there are, in these two explosives, other remarkable differences. Thus, in the Italian ballistite, at a density of 0-05, the volume of methane CH, is a mere trace, about 0.02 per cent., and it remains very much lower than is the case with any other explosive, being only 1-9 per cent. a: the density of 0.45. With the Norwegian, on the other hand, the CH,, although the volume at commencement only 0.04 per cent., is, at 0-45 density, 11 per cent. Again, as might be expected, from the large quantity of volume of hydrogen falls from more than 20 per cent. to CH, found in the case of the Norwegian ballistite, the about per cent.; in the Italian the H rises from about 8 per cent. to about 10 per cent., falling slightly at higher densities. In both explosives the N is practically constant at about 12 and 16 per cent. respectively, but there is a very great difference as regards the H2O. In the Norwegian the HO is constant at 14 per cent., there being no greater diffe ence than might be expected from errors of observation while, in the Italian, the H2O, which commences at density 0.05, with a volume of 29 per cent., falls at a No other explosive density of 0-45 to about 24 per cent. approaches the Italian ballistite in respect to the large volume of aqueous vapour formed, especially at low densities. In the tables are given the volumes in cubic centimetres per gram of the permanent and total gases, and curves have been drawn representing for the six explosives the observations of these volumes. In the case of five of the explosives there is, with increasing density, a very consider able decrease in volume, but with the Italian ballistite, throughout the range of the experiments, there is hardly any change. Curves representing these volumes are concave to the axis of abscissæ. In the tables are shown the units of heat, both for water fluid and water gaseous. Curves have also been drawn for the units of heat (water gaseous); the curves in this instance are all convex to the axis of abscissæ, and it may be noted that, where the volume of gas per gram is large, the units of heat are low, and that, where the volumes of gas are rapidly decreasing, the curves represent ing the amount of heat developed show a rapid increase. The next point to be considered is, the data being as is shown in the tables, what temperature are we to assign to that generated by the explosion? With the view of the author resorted methods (1) Knowing with very considerable accuracy the studying the question, units of heat (water gaseous) generated by the explosion, and having determined approximately the specific heat of the gases, the temperature of explosion should be given by the equation 1= gram units of heat to 10 (2) Knowing also with considerable accuracy the pressure at any given density, and knowing the pressure when the volume of gas generated is reduced to the temperature of o° C., and a pressure of 760 mm. of mercury, th temperature is given by the equation |