54 



POPULAR SCIEI^rCE ITEWS. 



[April, 1888. 



the sand, has thus far maintained his road-bed 

 without deterioration. The problem of a water- 

 supply was solved by bringing water in pipes from 

 mountains that skirt two hundred miles of the 

 route, also by canals from the Murghab ; while 

 artesian wells are the source of supply between 

 Merv and the Oxus. In a region that is destitute 

 of fuel, and where the cold is at times intense; 

 petroleum has been utilized to drive the locomo- 

 tives and to heat the sixty railroad stations along 

 the way. Russia may indeed be proud of the suc- 

 sess, now well assured, of her unique and astonish- 

 ing experiment in railroad-building. — New York 

 Sun. 



A SIMPLE THERMOSCOPE. 



For a year past there has existed in Berlin a dis- 

 infecting establishment, in which all objects that 

 have been in contact with persons suffering from a 

 contagious disease are submitted to the action of 

 superheated steam. The disinfection is not re- 

 garded as perfect until the entire mass has reached 

 the elevated temperature of the steam; and in 

 order to make sure that such temperature has been 

 everywhere reached, Herr Merke, the director of 

 the ^loabit Hospital, has devised a simple appara- 

 tus, which he introduces into the interior of the 

 mass to be treated. It consists of two pieces of 

 wood jointed at the centre, and the ends, a, a, of 

 which (Fig. 1) are held in contact by a spring, and 

 are provided with pieces of metal, c, c. The other 



ends, b, b, are provided with three metal eyes, — two 

 on one face, and one on the other. When the ends 

 ft, h, are brought together, they are held in position 

 by passing through the eyes a small pin formed of 

 an alloy fusible at 100° C. (212° F.). When 

 the apparatus is exposed to such a temperature, 

 the pin melts, and the spring / brings the metal 

 parts c, c, in contact. As the wires of a pile are 

 connected with the two metal surfaces at the points 

 e, e', a circuit is established as soon as a contact 

 takes place, and thus rings an electric bell. — La 



Lumiere Electrique. 



— • — 



ELECTRIC "SUNSTROKE." 



That portion of man's inheritance that consists 

 of " ills " seems to be daily increasing. M. Defon- 

 taine, doctor-in-chief to the Creusot Steel Works, 

 in a paper read before the French Society of Sur- 

 geons, states that workmen employed in operating 

 the electric forges at Creusot are subject to a form 

 of sunstroke which he attributes to the intense 

 light radiated from the focus of the forge. Ordi- 

 nary arc lamps are incapable of producing such 

 effects, as the light is not sufficiently intense; but 

 these forges emit a light of more than a hundred 

 thousand candles from a few square centimeters of 

 surface, producing on men exposed to their glare 

 physiological consequences previously unheard of. 

 Frequently, after two or three hours' work, the 

 men complain of pains more or less intense in the 

 neck, the face, and the forehead, simultaneously 

 with which the color of the skin is changed to red- 

 dish brown. Further, in spite of the precaution 

 taken by the men of shielding their eyes with dark 

 glasses, the retina is affected to such a degree that 

 for some minutes after ceasing work the operatives 



are totally blind to all objects illumined with com- 

 mon daylight, nor is perfect vision restored till 

 nearly an hour after. The conjunctiva are irri- 

 tated, and remain in a state of congestion for forty- 

 eight hours ; and this is accompanied by a painful 

 feeling, as of some foreign body introduced under 

 the eyelids. The secretion of tears is augmented, 

 a constant flow being kept up for twenty-four 

 hours, during which the patient suffers from in- 

 somnia, due to pain and the abnormal flow of tears, 

 and possibly also to fever. During the following 

 days the skin peels off the face and neck, which 

 become of a deep-red color, fading away about the 

 fifth day. In cases of ordinary sunstroke, heat 

 may have some influence; but in those considered 

 above, the whole effect is due solely to the action 

 of an intense light. — Engineering. 



A MUCH-NEEDED INVENTION. 



Notwithstanding the large number of fountain 

 pens, stylographs, and similar writing devices, the 

 majority of which are but vanity and vexation of 

 spirit, nothing has yet supplanted the old-fa,sh- 

 ioned lead-pencil in efficiency and reliability. It 

 is, however, a great annoyance to constantly stop 

 and fashion a fresh point, with the accompanying 

 search for a penknife, and the disposal of the dust 

 and shavings. The pencil sharpeners in common 

 use make only a point so short and blunt that the 

 sharpening process must be repeated every few 

 minutes What is needed is some device which 

 can be sold at a low price, and which will cut a 

 long, sharp, tapering point, such as at present can 

 only be formed by a penknife in the hands of an 

 expert sharpener. If some such improved form of 

 pencil-sharpener could be properly brought before 

 the public, the inventor would doubtless gain a 

 large fortune as the reward of his ingenuity. 



CHEMICAL NOTES. 



Separation of Nickel and Cobalt. — M. 

 Baubigny announces j*hat from solutions contain- 

 ing both these metals, he can obtain, by a judi- 

 cious use of sulphuretted hydrogen, a perfectly 

 pure sulphide of either of the above. 



Thallium in Platinum. — After having de- 

 tected thallium in platinum wire and foil bj' spec- 

 tral analysis, Mr. II. N. Warren endeavored to 

 separate the metals. Ten grams of the wire were 

 dissolved in nitro-hydrochloric acid, and after evap- 

 oration to dryness, and resolution in very dilute 

 nitric acid, hydriodic acid was added, and the thal- 

 lium precipitated as iodide. The proportions of 

 thallium found varied from 0.02 to 0.1 per cent, 

 the wire containing more than the foil. Alloys of 

 platinum and thallium containing 0.5 per cent of 

 the latter are useless for wire, and 2 per cent thal- 

 lium gives an alloy fusible at a red heat. 



Ozone from Pure Oxygen. — This was the 

 title of a paf)er lately communicated to the Chem- 

 ical Society of England by Messrs. W. A. Shen- 

 stone and J. Tudor Candall. The authors describe 

 an apparatus in which oxygen has been prepared 

 and stored without the possibility of air gaining 

 admittance. So far as it is possible to determine 

 the purity of the gas by tests, it would appear cer- 

 tain that it has contained at most 35V7 of nitrogen. 

 The oxygen has been collected and sealed up in 

 glass tubes containing phosphoric oxide, in contact 

 with which it has been kept for periods ranging 

 from eight weeks to eight months. Subsequently 

 it has been submitted to the action of electricity, 

 and the ozone produced has been nieasured. In 

 one experiment made at 10° C, no less than 11.7 

 per cent of the oxygen taken was converted into 

 ozone. This is a considerably higher proportion 



than has been obtained either by Brodie or by 

 the authors from ordinary oxygen when similar 

 means of electrification are employed, but not so 

 high as was obtained by Andrews and Tait, who, 

 however, worked in a different way, and the exact 

 value of whose results is uncertain, in consequence 

 of the tendency of the sulphuric acid that they 

 used in their gauges to absorb ozone. 



PRACTICAL RECIPES. 



A New Soldering Fluid. — Take two ounces 

 alcohol and put it into a bottle, and add about a 

 teaspoonful of chloride of zinc, and shake until 

 dissolved. 



Mix some finely powdered rice with cold water, 

 so as to form a soft paste. Add boiling water, and 

 finally boil the mixture in a pan for one or two 

 minutes. A strong cement is thus obtained, of a 

 white color, which can be used for many purposes. 



Impermeable and Transparent Paper. — 

 A French journal gives the composition of a prep- 

 aration for waterproofing fabrics, leather, etc., of 

 which the formula is as follows: — 



Turpentine paste 6 kilos. 



Tallow 1..5 " 



Wax 0.5 kilo. 



Styrax (necessary, and not optional) 0.2 " 



The inventor has since found that a homogeneous 

 substance is obtained. He now proposes to apply 

 this mixture to paper, in order to make it transpar- 

 ent and impermeable to air or moisture. 



To Prevent Steel Implements Rusting. 

 — The following is said to be a good applica- 

 tion to prevent metals rusting: " Melt one ounce 

 of resin in a gill of linseed oil, and while hot mix 

 with it two quarts of kerosene oil. This can be 

 kept ready to apply at any time with a brush or 

 rag to any tools or implements required to lay by 

 for a time, preventing any rust, and saving much 

 vexation when the tool is to be used again. 



To Copy Engravings. — An exchange gives 

 the following method, which may be worth trying; 

 but it should not be used upon engravings of 

 any value, as the original would probably be 

 spoiled: " Place the engraving a few seconds over 

 the vapor of iodine. Dip a slip of white paper in 

 a weak solution of starch, and when dry in a weak 

 solution of oil of vitriol. When again dry, lay a 

 slip upon the engraving, and place both for a few 

 minutes under a press. 'I'he engraving will be 

 reproduced in all its delicacy and finish. Litho- 

 graphs and printed matter cannot be so transferred 

 with equal success." 



Black Varnish. — To make a good black 

 varnish for ironwork, take eight pounds of asphal- 

 tum and fuse it in an iron kettle, then add two 

 gallons of boiled linseed oil, one pound of litharge, 

 one-half pound of sulphate^ of zinc (add these 

 slowly, or it will fume over), and boil them for 

 about three hours. Then add one and one-half 

 pounds of dark gum amber, and boil for two hours 

 longer, or until the mass will become quite thick 

 when cool. After this it should be thinned with 

 turpentine to the proper consistency. 



Black Coating for Brass Ob.ject8. — The 

 above composition is made by dissolving 1.05 

 ounces carbonate of copper, while being well 

 stirred, in 8.80 ounces of spirits of ammoniac, 

 17.60 ounces of water being added to the solution. 

 The brass objects should have been well polished 

 with emery paper, and are fastened to brass or 

 copper wires. They are plunged for a short time 

 in the solution, and when completely blackened are 

 rinsed in water. They are then dried in sawdust, 

 and finally rubbed with oil varnish diluted with oil 

 of turpentine. This black coating is said to be 

 durable, and to stand exposure in the open air. 



