420 



SCIENCE. 



[Vol. XIII. No. 330 



often a good one ; and a bright ruling-point always gives a 

 " scratchy " grating. When all goes well, it takes five days and 

 nights to rule a six-inch grating having 20,000 lines to the inch. 

 Comparatively no difficulty is found in ruling 14,000 hues to the 

 inch. It is much harder to rule a glass grating than a metallic 

 one ; for to all of the above difficulties is added the one of the 

 diamond-point continually breaking down. For this reason. Pro- 

 fessor Rowland has ruled only three glass gratings, one of which 

 has been lost, and the other two are kept in his own laboratory. 

 These two were used by Dr. Bell in his determination of the abso- 

 lute wave-length of the D lines. 



— Among the interesting and successful recent inventions is a 

 rolling-mill for producing sheet metal direct from the molten state, 

 instead of rolling it from a billet or bar. A machine of this char- 

 acter has been at work for several months at the can-factory in 

 Maywood, near Chicago. It is used for making sheet solder, six- 

 or eight inches wide, and yJuu of an inch thick, which it produces 

 at the rate of 400 feet a minute. T!ie Engineering and Mini7ig Jour- 

 nal describes the apparatus as consisting of hollow rolls with 

 cold water running through them. The water is introduced 

 through the axles, and the rolls are of sufficient size to at once 

 change the jet of melted metal into solid form as fast as it is fed. 

 The powerful compression exerted by rolls upon the molten metal 

 in forcing it between the two surfaces, and at the same time chan- 

 ging it to a solid body, tends to give to the sheet an even and highly 

 finished surface. The inventors of the machine believe that the 

 principle could be successfully applied to the rolling of Bessemer 

 steel, as well as to softer metals. Mr. O. W. Potter, and other 

 officers of the North Chicago Rolling Mill Company, recently ex- 

 amined the machine, and expressed themselves as being favorably 

 impressed with its work. 



— The Railroad Gazette calls attention to a double locomotive 

 for the Indian State railways which is a novel departure from the 

 common practice. The design is really a permanent double-header ; 

 that is, it is intended for use when the conditions are such as to re- 

 quire the use of two locomotives of the ordinary type, continually 

 in tandem. This arrangement removes the necessity for two 

 tenders, and renders easier the transmission of signals from one 

 cab to another. There is nothing in this arrangement to criticise : 

 it is really almost the only plan upon which locomotives of great 

 capacity can be constructed with any approach to a minimum of 

 weight per running foot of track. This general plan is not 

 new in America, however. The well-known William Mason, of 

 the Mason Locomotive Works of Taunton, Mass., constructed 

 locomotives on this general plan many years since ; and recently 

 the South Side Rapid Transit Co. of Chicago, while investigating 

 the possibilities of extending the usefulness of the proposed struc- 

 ture in years to come, decided that the adoption of a locomotive of 

 a design similar to the one described above would enable them to 

 haul nearly double the number of cars around the sharpest curves 

 without increasing the load per running foot of the structure. 

 Engineering, London, contains further description, together with 

 an inset showing the locomotive quite completely. 



— Gardeji and Forest states that in the garden of Professor 

 Charles N. Shepard, Charleston, S.C, is a rose remarkable for its 

 size and vigor. The original stock, a Banksian rose, was planted 

 more than fifty years ago ; but, at heights varying. from ten to fif- 

 teen feet, grafts of Marechal Neil, Marie Van Houtte, Devoniensis, 

 Cloth of Gold, Madame Eugenie A^erdier, and other choice varieties, 

 have been inserted, and these have made wonderful growth. The 

 trunk at the base is nearly a foot and a half in diameter ; and the 

 branches cover two trellises, each some forty feet long and twelve 

 feet wide, besides rioting over a piazza sixty-five feet long and for- 

 ty-five feet high, while the topmost shoots are aspiring to cover the 

 roof. From a photograph it can be seen that this great vine was 

 thickly covered from bottom to top with finely developed flowers. 



— Our own missionaries in China frequently allude to cases of 

 opium-poisoning, says The Missionary Herald. They are often 

 summoned in haste to treat those who have by this method at- 

 tempted suicide. Rev. Mr. Dixon, a missionary of the English 

 Baptist Mission at Tai-yuen-fu, reports, that, during the three 

 years he has been connected with the mission, he has attended 



some thirty-six cases of attempted suicide by opium. He affirms 

 that nine out of every ten men and women smoke the drug, be- 

 ginning about twenty years of age, some of them earlier. The ex- 

 cess in this indulgence is such as to impoverish the people, and 

 the poor wretches who are unable to obtain the supply they crave 

 often end their sufferings by borrowing enough to destroy life. In 

 Mr. Dixon's list of cases, there are young men and old men, girls 

 and wives, beggars and officials. One of the occasions which 

 frequently leads to this rash step is anger which has been excited 

 by some trivial circumstance. Opium is an awful scourge in China, 

 and brings in its train innumerable evils, of which, perhaps, opium 

 suicide is not the worst. 



— Four locomotives to be run by soda, which takes the place of 

 fire under the boiler, have been built in Philadelphia, says the Rail- 

 ivay Age, for service on the streets of Minneapolis, Minn., where 

 steam-engines are forbidden. The engine is about sixteen feet 

 long, entirely boxed in, with no visible smoke-stack or pipes, as 

 there is no exhaust or refuse. The boiler is of copper, eighty-four 

 and one-half inches in diameter and fifteen feet long, having tubes 

 running through it as in steam-boilers. Inside the boiler will be 

 placed five tons of soda, which, upon being dampened by a jet of 

 steam, produces an intense heat. In about six hours the soda is 

 thoroughly saturated, when the action ceases. A stream of super- 

 heated steam from a stationary boiler is then forced through the 

 soda, which drives out the moisture, and the soda is ready for use 

 again. The exhaust steam from the cylinders is used to saturate 

 the soda, and by this means all refuse is used. These engines are 

 the first of their kind that have been built in this country. They 

 will have the same power as those used on the New York elevated 

 roads. Soda-engines are used in BerUn and other European cities 

 very successfully, and they also traverse the St. Gothard Tunnel, 

 under the Alps, where the steam-engines cannot be used, because 

 the tunnel cannot be ventilated so as to carry off the noxious gases 

 generated by a locomotive. 



— In 1864 a hot-headed French inventor offered to contract for 

 churches and cathedrals, including a peal of bells, says The Paper 

 Makers' Circular, to be constructed entirely of paper. From 

 chimes to cannons was but one step, and the Gallic inventor an- 

 nounced his readiness to supply a train of artillery of any given 

 caliber, made of the same material. Building-paper is enjoying a 

 perfect boom just now, and is proving a fine material in the hands 

 of architects and builders for several uses, inside and out. The 

 advantages, briefly stated, are : continuity of surface, or its adapta- 

 bility for making into rolls of almost any width and length, and 

 flexibility ; or by glueing several layers together it may be made 

 stiff, and will stop the passage of air because of the absence of 

 joints ; unlike wood, it has no grain, and will not split ; it is unaf- 

 fected by change of temperature, and thus has an advantage over 

 sheet-metal for roofing materials ; though in its natural condition 

 it is affected by moisture, it canvbe rendered waterproof by saturat- 

 ing with asphalt or by various other methods ; being a non-reso- 

 nant body, it is well fitted to prevent the passage of sound ; it is a 

 non-conductor of heat, and can also be made of incombustible 

 material, like asbestos, or rendered resistant to fire by chemical 

 treatment. 



— The electrical census machine is described as follows in The 

 Engineering and Mining Jour7tal : " The census-collector will 

 call with his printed blank, and answers to questions will be writ- 

 ten in the usual way. These sheets will then be placed before a 

 person who operates a machine which may be likened to a type- 

 writer, except, that, instead of the usual ink-mark on paper, small 

 round holes are punched in a card. The cards, one for each per- 

 son, are about 6* inches in length by 3 inches in width, and the 

 particular position of a hole in a card indicates an answer to some 

 of the questions in the printed blank. As many as 250 items of 

 information can be punched out upon a card, although no one card 

 would ever have more than one-tenth part of the whole number : 

 as, for example, no one person can be classed as both white and 

 black, American and foreign born, and if foreign born he can only 

 come from one country. These cards, when punched, are placed 

 one at a time in a sort of press, and a lever operated by one hand 

 is brought down, when a series of pins are brought against the 



