334 



NATURE 



[July 31, 1890 



These values of tm. and t'm are the initial stresses or circum- 

 erential tensions ; and as the powder pressure po increases them 

 by equal amounts, their difference is unaltered ; so that /„, - An is 

 the same for the initial stresses or the firing stresses ; and we 

 may calculate the shrinkage, S, by the above formula from the 

 values of the firing stresses, or of the initial stresses ; the former 

 being chosen, as given more directly when the maximum allow- 

 able tensions, represented by tm, are given. 



(43) As a numerical illustration, let us calculate the shrinkages 

 in the American 8-inch gun, taking the previous results of § 22, 

 and M = 12,600 (tons per square inch) for all the coils. 



Then the final contraction of the bore 



oSi 



2ro -r- M = 19-9 



12,600 = o'oi6, 



or 16 thousandths of an inch ; and similarly, 



jSj = 127 X 14 -=- 12,600 = 0*014 ; 

 2S3 = 107 X 22 -^ 12,600 = 0'0I9 ; 

 3S4 = 3*6 X 26 -^ M = 0*007 ; 

 4S5 = 8'i X 32 -f- M = o'02i, 



the elongation of the external diameter of the last coil. 



Lieutenant Rogers Birnie, following Clavarino ("Note on the 

 Construction of Ordnance," No. 6), calls the extension or co7n- 

 pression the relative elongation or relative contraction ; so that 

 the above values of pSj, ^Sa, 2S3, 3S4, 4S5, must be divided by 

 10, 14, 22, 26, 32, to obtain his values of the relative elongation 

 or contraction ; and then, by § 37, 150 thousand times the 

 relative elongation or contraction is the number of degrees 

 Fahrenheit a jacket or coil must be raised in temperature to be 

 expanded sufficiently so as to slip over the inner cylinders. 



A. G. Greenhill. 

 {To be continued.') 



THE TOKIO TECHNICAL SCHOOL. 



'HPHE Japan Weekly Mail in a recent article describes the 

 -'- Tokio Technological School, situated at Asakusa, a suburb 

 of that city. The inclosure in which the school buildings stand 

 formerly belonged to the Shogun's Government, and was used 

 for the storage of rice. Several of its storehouses, which were 

 ranged round a creek or blind canal leading off the river, still 

 remain, and are utilized by the institution. A frame building of 

 two stories, the chief modern portion, faces the roadway and 

 runs at right angles to the creek. Here are the offices, show- 

 rooms, and lecture-rooms ; the workshops are to be found 

 between this building and the river. There are two great 

 departments in the school, the Technological and the Mechanical. 

 Of these the former is the more varied and interesting. To it are 

 attached a dyeing shop, porcelain and glass furnaces, and techno- 

 logical laboratories ; to the mechanical department are attached 

 a drawing office, a pattern shop, and a foundry. 



The history of the school begins with its foundation in 1882, 

 for the purpose of training foremen and managers for manufac- 

 tories, and instructors for industrial schools. It was intended 

 that the course of instruction should include all branches of 

 industrial education concerned with arts and manufactures. 

 The course was to extend over three and a half years, of 

 which the first year should be devoted to general preparatory 

 instruction and the others to special training in some par- 

 ticular branch. Next year certain alterations were made, making 

 the course one of four years, and raising the standard. In 

 August of that year the first batch of students, numbering 

 sixty in all, were admitted. The school was shortly afterwards 

 brought into connection with the Imperial University, and placed 

 under the control of that institution — a step which led to a com- 

 plete change in its curriculum. The preparatory course was 

 abolished, and a short complete course, extending over two 

 years, was instituted. Again, in 1888, a new Imperial decree 

 severed its* connection with the University, and placed it under 

 the direct control of the Education Department. The school 

 set itself anew to remodel its course of instruction, abolishing 

 the short general course and resuming the course of three years ; 

 and elective courses were established with the view of making 

 the school more popular and generally useful to mechanics and 

 craftsmen. The laboratories and workshops are each provided with 



NO. 1083, VOL. 42] 



responsible superintendents, foremen, and assistants. The general 

 direction is in the hands of a Committee, consisting of the manager 

 of the school, two officials of the Education Department, and 

 two officials of the Department of Agriculture and Commerce. 

 Candidates for entrance to the regular courses must be not 

 under seventeen nor over twenty-five years of age, and unless 

 they have passed satisfactorily through a normal or middle 

 school, must undergo an examination in Japanese, arithmetic, 

 algebra and geometry, physics and chemistry, and English 

 translation. Students sent up by local governments need not 

 undergo this examination. The elective courses have been in- 

 stituted for the benefit of artisans and mechanics, who, having 

 no general scientific training, are anxious to study some part of 

 the regular course. These candidates receive this privilege only 

 when the convenience of the school admits of it, and are allowed 

 to study for two years, taking one or more of the subjects im- 

 mediately connected with their special crafts. An elective 

 student must be at least seventeen years of age, and must have 

 followed, for more than one year, some trade having special 

 relation to the subjects of instruction which he has chosen. The 

 fee paid by these students is about 3^. monthly. 



In the mechanical engineering section-boilers, steam-engines, 

 force-pumps — these last happen now to be in great demand in 

 Japan as an improvement on the clumsy well-bucket — and 

 sawing-machines are manufactured. The shop is also 

 prepared to execute orders for steam and hot-water heating 

 apparatus, and has already fitted up the new Engineering 

 College in the University grounds with a complete set of 

 hot-water pipes and fittings. All the casting and founding 

 required by the College are carried out at the Asakusa School. 

 An improved pattern of perforating machine, now in use at the 

 Imperial Printing Office, is also turned out. It is claimed for 

 this pattern that it possesses a superiority over the one in 

 common use in Europe for perforating stamps and other paper. 

 Experiments are likewise in process on printing-presses, with 

 the view of perfecting a machine for native use. The dyeing 

 department is chiefly concerned with practical instruction in 

 the best methods of fixing colours, rather than in any more 

 original researches. Of late years the importation into Japan of 

 aniline dyes has increased to such an extent that the total annual 

 value of these imports now exceeds ;i^35,ooo. Unfortunately, 

 although these colours are very attractive to buyers, their proper 

 use is still little understood. Silk, cotton, and other fabrics 

 which have been coloured by native dyers do not wash well, and 

 half the imported dye-stuffs run to waste. It is one of the 

 chief aims of the instructors in this department to teach artisans 

 how to fix these colours. Just now the school dye-shop is busy- 

 ing itself with this particular branch, and also with a series of 

 experiments on the dyeing of mountain silk. This silk, which 

 is soft in texture and durable in wear, refuses the ordinary dye, 

 a- circumstance attributable to the presence in it of a large- 

 amount of calcium carbonate. The pottery and glass depart 

 ment is associated with the name of Dr. Wagner, who has for 

 a long series of years enjoyed the confidence of the Japanese 

 Government. Dr. Wagner is admitted to be the best authority 

 on all matters connected with Japanese technology, and has 

 directed his particular attention to the fabrication of a ware 

 known in Japan as asahi-yaki, and elsewhere as Dr. Wagner's 

 faience. Unlike the Satsuma, which is also faience, but of a 

 much harder kind, this ware receives its decoration when in its 

 unglazed state, which is a manifest advantage. It is made 

 chiefly from a clay found in the Enya district of theTochigi pre- 

 fecture, with slight admixture of clays from other localities. 

 The colour of the faience when baked varies from white, having 

 a warm brown tinge, to lightish pink. Much of the asahi-yaki 

 is exported to Germany and to the United States, and a certain 

 amount to France, but little or none finds its way to Great 

 Britain. Artists are at work on the spot decorating the plates 

 and other articles preparatory to the receiving of the glaze. 

 The object which Dr. Wagner and his colleagues have in view 

 is technological and not artistic, and consists in perfecting 

 native potters in the manipulation of the material. 



■ SCIENTIFIC SERIALS. 



The Quarterly Journal of Microscopical Science for June 

 1890 contains : — On the embryology of a scorpion {Euscorpius 

 italictis), by Malcolm Laurie (Plates xiii.-xviii.). The develop- 



