Vol. XXIII. No. S.] 



POPULAR SCTETsTCE NEAVS. 



119 



Alterion for the Prevention of Corrosion 

 IN BoiLEiis. — An English elfctrician has invented 

 a material which he calls alterion, for the preven- 

 tion of corrosion in boilers. The interior is coated 

 with this, and currents of electricitv are passed 

 through the boiler, and from time to time reversed. 

 The formation of the scale is prevented by a layer 

 of hydrogen gas, which is deposited upon the inner 

 surface of the boiler. The reversed currents reform 

 the hydrogen into pure water, a thin layer of pure 

 water being thus kept all around the boiler. 



Japanese Clocks. — An interesting note, by Mr 

 Arthur A. Rambaut, on some Japanese clocks lately 

 purchased for the Dublin Science and Art Museum, 

 has been reprinted from the Proceedings of the 

 Royal Dublin Society. These clocks, though differ- 

 ing in other respects, agree in this particular, that 

 the time is recorded, not by a hand rotating about 

 an axis, but by a pointer attached to the weight, 

 which projects through a slit in the front of the 

 clock-case. This pointer travels down a scale 

 attached to the front of the clock, and thus points 

 out the hour. Mr. Rambaut has consulted several 

 persons who have been resident for some time in 

 Japan, but none of them have ever seen clocks of 

 like construction in actual use. A young Japanese 

 gentleman, to whom the specimens have been 

 shown, says that he has heard of such clocks being 

 used in rural parts of Japan about twenty or thirty 

 years ago, but that they have been almost completely 

 superseded by clocks made on the European plan. 



Transmission of Power Through a Bore- 

 hole.— Mr. Wm. Hall, manager of the Spring Hill 

 (N. S.) mines, gives the following account of the 

 successful completion of a winding plant, situated 

 on the surface, and hoisting from an underground 

 slope. A bore-hole four inches in diameter has been 

 put down from the surface to the bottom of the 1,300- 

 foot level, a depth of 600 feet perpendicular. An 

 engine and boiler have been placed in position on 

 the surface close to the bore-hole. Power is then 

 transmitted by means of a wire rope, and an arrange- 

 ment of pulleys at the top and bottom of the bore- 

 hole. Beside the wire rope in the bore-hole is 

 placed a signal cord. By means of this cord com- 

 munication is kept up between the engine men and 

 the man at the bottom. The first cost of the bore- 

 hole is not nearly so great as that of i,Soo feet of 

 steam pipes, while the cost of repairs, where pipes 

 are suspended from the roof by means of hooks, will 

 be entirely saved. Other repairs necessary to pre- 

 vent leakages in the pipes will also be obviated, thus 

 etfecting a very material annual saving. 



The Durability of Steel Rails. — A commis- 

 sion representing the various German railway com- 

 panies has published a report detailing the results 

 of observations made during six years on the dura- 

 bility of steel rails on German, Austrian, Hunga- 

 rian, Dutch, and Belgian lines, from which it 

 appears that the durability of a steel rail may be 

 reckoned on an average at thirty-five years, presum- 

 ing that the annual traffic be calculated at 3,430,000 

 tons, and the minimum and maximum of wear and 

 tear allowed to be 0.007 ^"^ 0.017 millimetres. The 

 average traffic on the German lines amounts in the 

 year to 3,430,000 tons, and represents twenty-eight 

 passenger and ten goods trains per diem. In esti- 

 mating the value of the above calculat'on, it must, 

 however, be borne in mind that before reaching the 

 maximum of wear and tear named, the rail would 

 probably have to be condemned on account of the 

 roughness of its surface. On the Housinger line, 

 where there are neither steep gradients nor sharp 

 curves, and the brake consequently comes but little 

 into play, the wear only amounted to one millimetre 

 for about 10,000,000 tons. 



^ODie, Barnj, ai^d Gardeij. 



OUR CLOTHING. 



The first articles of clothing worn by man- 

 kind were, imdoubtedly, made from tiie skins 

 of animals, hut, as civilization advanced, the 

 arts of spinning and weaving became known 

 at an early period, and wool, tlax, and other 

 animal and vegetable products were used to 

 form fabrics of constantly increasing fineness 

 and beauty. 



Wool, the most important animal product 

 used for clothing, is really the hair of the 

 sheep, and has an analogous structure to the 

 true hairs of other animals. Like hair, the 

 wool fibres consist of an epithelium or outer 

 coating, a rind or body, and the pith or mar- 

 row filling the hollow interior. The epithe- 

 lium consists of small, thin plates, which 

 overlap each other like the shingles of a roof, 

 and to these plates or scales the wool owes its 

 valuable felting quality. A microscope of 

 moderate power will show this structure very 

 plainly. Wool, when clean and pure, con- 

 sists principally of an albuminoid sulphur- 

 containing substance termed keratin^ but, 

 as it occurs on animals, it contains much dirt 

 and suint. The suint contains a large pro- 

 povtion of greasy matter and potash, and is of 

 considerable value as a source of potash. 



Silk is another animal product, but is not 

 an organized structure, but simply a secretion 

 of the silk-worm, the larva of the Botnbyx 

 niori. The worm is produced from the egg 

 in the spring, and, after casting its skin three 

 or four times, spins a thread from a liquid 

 secreted by two glands situated near its head, 

 which immediately coagulates on coming into 

 the air. This thread is double and com- 

 pletely covers the worm, forming a cocoon 

 intended to protect it during the change from 

 larva to butterfly. The silk raisers, however, 

 do not allow the transformation to take place, 

 but kill the imprisoned worm, or pupa^ by 

 the application of heat. The cocoon is com- 

 posed of a single continuous thread, but it is 

 mi:ch too fine to manipulate, so the fibres of 

 from three to twenty cocoons are imwoimd at 

 one time and united into a single thread. 

 This unwinding of the cocoons is a very deli- 

 cate operation, and requires great care and 

 skill. From 250 to 900 yards of raw silk 

 fibre are obtained from each cocoon. 



Raw silk consists of two parts, — the fibre 

 or body, known as silk fibroin, and the gum- 

 like substance with which it is covered, known 

 as silk-glue or sericin. Only fibroin is .se- 

 creted by the worm, but this is superficially 

 oxidized to sericin when discharged into the 

 air. For most purposes the* sericin must be 

 removed before the silk is spun and woven, 

 but, when it is to be made into crape or 

 gauze, it is allowed to remain. 



Silk is quite soluble in hydrochloric acid, 

 and this reaction may be used to discover the 



presence of cotton or linen fibres when mixed 

 with it. A microscopical examination is, 

 however, the best and simplest test, as the 

 smooth, solid, unorganized appearance of the 

 silk fibre is very characteristic, and cannot be 

 mistaken for cotton, flax, or wool. 



The silk-worm feeds almost exclusively on 

 the leaves of the white mulberry tree, Morus 

 alba, and their culture and rearing form a 

 most important branch of agriculture in 

 Europe. Other silk-producing insects are 

 known and cultivated in China and India, but 

 their product is small and unimportant. The 

 culture of silk-worms in this country has not 

 yet pas.sed the experimental stage, although 

 there seem to be no great difliculties to be 

 overcome. 



The most important vegetable fibre is 

 cotton, and the magnitude and value of this 

 crop in the Southern States is well known. 

 It consists of the fine plant hairs which sur- 

 roimd the seed of the cotton plant, and is 

 principally composed of cellulose. The seeds 

 are separated from the cotton by machinery, 

 and the fibres spun and woven into an endless 

 variety of textile fabrics, with which a major- 

 ity of the world's inhabitants are clothed. 



The microscopical appearance of cotton is 

 very characteristic. It has the form of a flat, 

 twisted band, and cannot be easily mistaken 

 for other fibres. The cotton plant is culti- 

 vated in many other countries, especially 

 India and Egypt, but the United States is 

 still the principal source of tiie world's 

 supply. 



Flax is the fibre of the flax plant, Linum 

 usitatissimum, and its textile value has been 

 known for a long time. The fibre lies under 

 the bark, and is surrounded bv a gimimv 

 pectose substance, which was formerlv re- 

 moved by soaking in water and exposing to 

 the air till it rotted away, but acid and alka- 

 line baths are now used for the purpose, with 

 much more satisfactory results. The fibre is 

 then separated from the woody matter of the 

 stem by a process of beating and combing, 

 known as scutching and, after being cleaned, 

 is ready to be bleached, spun, and woven into 

 the beautiful fabric known as linen. 



Under the microscope, linen fibres appear 

 cylindrical and straight, being thus easily 

 distinguished from the flat, twi.sted fibres of 

 cotton. The microscopical examination of 

 the difl'erent animal and vegetable fibres is 

 very interesting, and only requires an instru- 

 ment of moderate power. Once seen,, the 

 characteristic forms cannot be forgotten, and 

 the knowledge is often useful in determining 

 the quality of a piece of dress goods. Linen, 

 like cotton, is principally composed of cellu- 

 lose. 



Clothing pos.sesses no warmth in itself, but, 

 as it is a more or less poor conductor of heat, 

 it prevents the escape of the bodily warmth. 

 Woolen fabrics contain a large quantity of 



