the teacher and assures a reasonable equality of standard; (3) that greater freedom of educational development is permitted when all students are not working to one cast-iron syllabus. The scheme seems to be promising, if only it does not become too hide-bound and too heavily tied up in red tape regulations. We shall watch it with interest, but our interest will speedily evaporate if it should develop merely into an examination system. It is essential in my opinion that it should encourage students to make progress in their profession, and to that end it should be associated in some way or other with the means of attaining corporate membership of the professional Institutions-in this case the Institution of Mechanical Engineers. GRANTS AND SCHOLARSHIPS. Amongst the things to which attention will be drawn at the conference is the proposed reduction of grants for scientific research and the reduction of the number cf national scholarships for Higher Education. These things are noted not only hecause such reductions gravely imperil scientific and industrial development, but also because the percentage reduction in estimates for these items is much greater than that for corresponding items in other branches of educational work. the It would almost seem that there is being carried out a definite policy for the starvation of higher work and for the removal of many rungs of that educational ladder about which so much is said whenever our education system is being appraised by our administrators. THE LABOUR PARTY AND TECHNICAL We welcome the interest which the Labour Party is taking in educational development, and particularly do we welcome the fact that Technical Education is no longer regarded by that Party with suspicion and distrust. That distrust no doubt arose from the mistaken idea that Technical Institutions were going to teach trades and provide employers with cheap labour; and that in some way or another they represented a form of subsidy to capital at the expense of labour. They are now regarded in a different light. It is seen instead that they provide a means of higher education within the reach and within the means of most people, and in that light they are being welcomed. OUR CHIEF WORKERS. In It is with great pleasure and satisfaction that I am able to report that the Council of this Association has been able to recommend the appointment of a stipendiary Secretary to assist the Honorary Secretary to carry out the ever-increasing labours of our Association. We have been well served by our voluntary workers in the past, but our work has grown so steadily, and latterly so rapidly, that we were imposing upon them an intolerable and impossible burden. particular, of course, did we burden Hon. Secretary, and we are tremendously grateful to Mr. Sirman for the splendid way in which he has responded to the calls made upon him. We are also very glad that he has consented to accept nomination for the Hon. Secretaryship for at least another year, and we look forward to some valuable workbeing done with the aid of the gentleman whom the Council has nominated for the stipendiary Secretaryship. our I would also like to offer congratulations to the Editor of our Journal (The Technical Journal), Mr. F. E. Drury, for his successful efforts. He had a difficult task in following our Mr. Abbott-I think that we may use the possessive pronoun-and his success is therefore all the greater. In Mr. Riley we have an Hon. Treasurer of unsurpassable merit. I am afraid that his work is so excellent and so faultless that it does not receive the publicity which it deserves, nor do we always express to him the gratitude that we feel. CONCLUSION. The first object of our Association as set forth in our Rules and Constitution, is to promote the interests of Technical Education generally. In that we are sincere, and our record of activity during the eighteen years of our existence is proof of that sincerity. The fact that we would also seek to safeguard the professional interests of our members does not detract from that sincerity. I can say with certainty that our organisation has been welcomed by the Board of Education and by the leading Education Authorities as the channel through which they can obtain the opinions of Technical Teachers-who put into practice the educational schemes-who know by experience the weaknesses and strength of the various parts and who know what Technical Education does and can do. The proper use of knowledge is in man's keeping, and it is his plain duty to use it for the benefit of mankind. Knowledge was never intended to be used merely as a form of mental adornment or for the external equipment of what might be called the mental fop. Much of it has been used for that purpose, and there has been too much mental snobbery in the ranks of those who should have shown to all the world that education gives to man that sweet reasonableness, balance, judgment, and kindly indulgence, which go to make the relationship between one man and another more nearly in accord with that great commandment, Love one another.' Our Association stands for the proper use of knowledge-not merely in the materialistic sense, but with a full sense of the responsibilities of civilisation. We may deplore many of the products of civilisation, but we have some responsibility for them, and it is our plain duty to so train the mind of man that he may be able to acquire that joy of living which can only spring from understanding satisfaction in his work, from the feeling that he is definitely creating, definitely achieving something worthy of achievement, and something in which he can take pride; and from the ability to lead fuller life in his hours of rest and recreation. a 50 terman using a suspension of the finely powdered material as it is insoluble. Heat and shake the solution for 15 minutes, and filter after adding the sodium sulphate according to his direction. Extract the precipitate with hot ethyl alcohol and precipitate with water. The new dye has a deep purple colour but very poor tinctorial value, dyeing silk only a pale lavender from alcohol solution as it is insoluble in water. This is probably due to the fact that apparently the hydrochloride is unstable and is hydrolyzed by water, for a qualitative analysis showed C, H, N, and S, but no chlorine. It was then analyzed for nitrogen according to the method of Fisher as were the other analyses. Calculated for CH, No S, N= 51 40 6 12.24% 12.03% Found N= {12.12% 14. Sulphonation of the Dye. was It was thought that the poor tinctorial value of the new substance might be due in part to its neutrality and extreme insolubility, so an attempt was made to sulphonate it with 15 per cent. fuming sulphuric acid. mixture The sulphonation diluted with water, neutralised with barium hydroxide, and the precipitated barium sulphate was filtered off. The resultant yellow solution was concentrated and allowed to crystallise, depositing pale yellow plates, but as the hue of the dye appeared to be destroyed in the process, no further work was done on it. 15. Nitro-tolyl Benzothiazole. In connection with the second and third purposes of this investigation, it was considered desirable to prepare some of the derivatives of the paratolyl benzothiazole, especially the nitro ones, because the nitro group frequently functions as an odorophore, as in the synthetic musks; and the amino derivatives, which would be isomeric with the valuable dehydrothiotoluidin which has already been mentioned a number of times. The nitration of paratolyl benzothiazole may be accomplished with fuming nitric acid or a 1:1, by volume, mixture of conThe centrated sulphuric and nitric acids. best procedure for moderate quantities follows: 50. Gatterman, Practical Methods of Org. Chem. 51. Fisher, Lab. Man. of Org. Chem. In a small flask dissolve 2.5 g. of paratolybenzothiazole in 10 cc. of concentrated sulphuric acid, and add 10 cc. concentrated nitric acid. The solution becomes warm at once, nitrogen tetroxide is evolved, and 'he colour changes from yellow to reddishbrown. Heat on a water bath for one hour. Let cool and pour into 100 cc. of water. A bright orange-yellow precipitate settles out, which on drying weighs 3 g. The coloured impurities may be removed by warming on a water-bath with about 50-80 cc. of ethyl alcohol, and the residue can then be dissolved in 50 cc. of hot toluene, which on cooling deposits the mono-nitro derivative in pale cream-coloured, odourless crystals, M.P. 219.5° C. (cor.). Calculated for CH, O,N2S N= Found N= { 10.38% N = { 10.56% 10.51% The nitration proceeds smoothly and quantitative yields according to the equation CH,,NS+HNO,C,,HO2N,S+H2O may be obtained from any weights. Toluene is a remarkably good solvent for purifica- · tion, as the difference in solubility with temperature is strikingly great. 16. Aminotolyl Benzothiazole. The nitro derivative was then reduced, using zinc or tin and hydrochloric acid according to the method of Gatterman. The amine forms an addition product with the metallic salts, from which it is a little difficult to remove the metal, and may be crystallised from ethyl alcohol, amyl alcohol, or toluene, none of which are good solvents as the substance is quite insoluble, but the last is the best of the three, and yields the base in small brown crystals, which are much lighter in colour on purverisation and melt at 229° C. (cor.). Amyl alcohol and toluene solutions exhibit a bluish-green fluorescence which is characteristic of most of the benzothiazoles. Calculated for C1,H12N2S N= 11.67% 14 12 Found N= { 11.80% 11.90% 17. Azo Dyes from Amino Paratoly! Benzothiazole. Amino paratolyl benzothiazole is not a dye, but can be diazotized on the fibre and coupled with the usual materials, and yields a series of direct cotton colours. This was done according to the method which will be described later, with the results noted in the table. With the amines as couplers, the developer was made up as a 2 per cent. solution by weight, using sufficient glacial acetic acid to dissolve them, and after the cloth was immersed, the bath was neutralised with 10 per cent. NaOH, thus precipitating the dye out in the fibres of the material. Other acids do not appear to give satisfactory results. Depth. 1. Phenol Colour. Yellow Good Yellow-brown 19. 20. (6) 21. (7) 22. (6) +ammonia Yellow + B naphthol + B naphthol Orange +p cresol These colours are all as fast to light, soap, bleaching, etc., as the corresponding azo colours from dehydrothiotoluidin, and the tinctorial value in general appears to be much better, particularly of the browns, where it is really quite remarkable. To put it colloquially, "a little will go a long way, The specimens were all dyed from a 1 per cent. solution of the amine in the presence of sodium chloride according to the method given later, dried, and steam pressed. a con The bis-diazo compounds are better than the primary diazo ones, both from sideration of variety, and of depth of colour, particularly those of alpha and beta-napthylamines from which, as well as those given, a good series of browns may be obtained. It would be interesting and illuminating to determine if a series of greens could be obtained from this base by diazotizing and coupling with dioxynapthalene disulphonic acids, as in the case of dehydrothiotoluidin, 7 but unfortunately, the last two reagents were not available, and all other attempts to prepare a green or blue failed, with the exception of the one purple found in the chart, which, however, it is interesting to note, begins to approach these in structure. 18. Para (2 Benzothiazolyl) Benzoic Acid. Paratolyl benzothiazole contains a methyl group which it should be possible to oxidize to the corresponding carboxyl group by methods analogous to other side chain oxidations. This was first attempted by means of potassium permanganate in neutral solution in the presence of magnesium sulphate according to Fisher. The permanganate was reduced, but the final yield of the expected acid from 5 g. of the thiazole was so small that it could only be crystallised once, and the amount was too small to proceed further with. The substance obtained was yellow white in colour and appeared to decompose, but did not melt up to 270°. substance resembled that in the first experiment in every way, crystallising in microscopic white needles from alcohol, which darkened but did not melt up to 270° C. 19. Primulineazo-Benzoylene Urea. It has been shown 69 that 1:3 dioxyquinolin is particularly suited, in combination with primuline diazotized on the fibre according to the process invented by A. H. Green, to give acid, light, and wash fast orange colours on cotton. The procedure is given in the patent, for example: one requires for a 2 per cent. primulin developed colour, a mixture of 1 per cent. 1:3 dioxyquinolin as the sodium salt, and 1.5 per cent. sodium carbonate in which the material is immersed after coming from the diazotizing bath. Dioxyquinolin gives a clear orange colour of greater acid-, base-, and wash-fastness than the corresponding phenol or resorcin developed colours. was therefore thought that benzoylene urea which resembles dioxyquinolin closely, would also couple to give a dye exhibiting these valuable properties. It The procedure used in dyeing was a modification of that described in the Badische Co. Pocket Guide (p. 101), and as practical methods of this kind are not as readily accessible as might be thought at first, a brief summary is given. a (a) Before dyeing, boil the cotton in water solution of sodium carbonate and wash with water. (b) Enter the cotton into the dye bath (2 per cent. primulin) and work at a boil for 11⁄2 hours, adding 5-30 lbs. of crystalline Glauber's salt or 2 to 10 lbs. of sodium chloride for 100 lbs. of cotton. (c) Dye cotton as just given and treat for one-half hour in a fresh, cold diazotizing bath, using 3 lbs. of sodium nitrite and 84 lbs. of concentrated hydrochloric acid per 100 lbs. of cotton, keeping the temperature below 50° F. by the addition of ice. Add the sodium nitrite to the acid, not vice versa. (This is an unnecessary precaution for laboratory procedure.) Rinse once in cold acidified water and enter into the developer for one hour. (d) A typical developer bath (for ingrain red) consists of a 1 per cent. solution of beta napthol dissolved in warm water by means of an equal weight of sodium hydroxide. For small amounts of material a 100 cc. 69. Bad. An. and So. F., D. R. P., 210, 453; Friedländer, 9-411. The tinctorial value of the new dye is just as good as ingrain red, and it appears to be of about the same order of fastness as the latter, except to prolonged exposure to light, but this is more than counterbalanced by its greater fastness to alkali. are PART B-DEHYDROTHIOTOLUIDIN. This compound is prepared commercially, directly from paratoluidin and sulphur, and the methods are at variance on two principal points, the manner of conducting the fusion, which is either by a mixture of only the two substances in molecular quantities, or by the addition of a diluent such as napthalene or an excess of partoluidin, and the method of purification. In any event, much primulin and other substances formed simultaneously, and their formation is greater in the presence of an excess of sulphur, and since dehydrothiotoluidin is the more valuable of the two, this is to be avoided. Of the patents already mentioned the basic ones are those of Kalle and Co., of Biebirch am Rhein (a duplicate of the original one mentioned earlier with some changes), and of Leopold Casella and Co. Three methods of separation of the mixed bases which form the melt are available. The Casella patent appears to do so by a 44 44. Dahl & Co., D. R. P., 35790; Friedländer, 1, 536. Kalle & Co., D. R. P., 92011; Friedländer, 4, 824. Bayer & Co., D. R. P., 65402; Friedländer, 3. 752. Casella & Co., D. R. P., 53938; Fried- Picke, Lange & Co., D. R. P., 52509; Höchster Farbw. Co., D. R. P., 104. Ingrain Red. Fast Bleeds out Not bleached Fast difference in the basicity of the two compounds, claiming that dehydrothiotoluidin is more soluble in a 30 per cent. by weight solution of sulphuric acid, while the Kalle patent effects this result by taking advantage of the fact that the ammonium salt of dehydrothiotoluidin sulphonic acid is less. soluble in water than the corresponding derivative of primulin. The third method consists in distilling the melt in vacuo by which only dehydrothiotoluidin comes over, but from a commercial standpoint this method is unsatisfactory, and although it is being used at present, if there was a way of avoiding it, it would be abandoned due to the difficulties of the process in the plant. Preliminary experiments showed that, in spite of the number of patents and the volume of literature on this subject, practical directions for the synthesis were noticeably lacking, and a critical study of all the methods was made with a view to supplying this deficiency from a laboratory standpoint at least. 1. The Casella Method. The melt was prepared according to the patent directions in each case, substituting grams for "parts" in the wording of the patent. After heating, the fusion mixture was repeatedly extracted with 500 cc. portions of 30 per cent., by weight, sulphuric acid until nothing further was dissolved. The liquid extract was then drowned in water, or later diluted only a little more, and neutralised while warm with sodium hydroxide, which precipitates the mixed bases in a form which is more readily filtrable. The first factor investigated was the effect of length of heating time on the 70. Bogert and Scatchard, J. A. C. S., 41, 2052 (1919). |