38 



POPULAR SCIENCE NEWS. 



[March, 1888. 



mass is exploded. The power of all these sub- 

 stances is due to the paradoxical element nitrogen, 

 which is by itself the most neutral and inactive 

 of all the elements, but, when forced into chemical 

 combination, usually confers an element of weak- 

 ness upon the entire molecule of which it forms a 



part. 



— « — 



THE FLIGHT OF BIRDS. 



At a meeting of a scientific society last fall, 

 Professor W. P. Trowbridge read an interesting 

 paper on the above subject. 



It has always been a puzzle how the muscular 

 action necessary to keep birds on the wing so long 

 as they often remain could be possible ; and 

 Professor Trowbridge explained the recent dis- 

 covery by his son, which is, that birds of prey and 

 some others have the power to lock securely to- 

 gether those parts of the wing holding the extended 

 feathers, and corresponding to the fingers of the 

 human hand. The action of the air on the wing 

 in this condition extends the elbow, which is pre- 

 vented from opening too far by a cartilage, and 

 the wings may keep this position for an indefinite 

 length of time, with no muscular action whatever 

 on the part of the bird. While resting in this 

 way, the bird cannot rise in a still atmosphere; 

 but if there be a horizontal current, it may allow 

 itself to be carried along by it, with a slight ten- 

 dency downward, and so gain a momentum by 

 which, with a slight change of direction, it may 

 rise to some extent, still without muscular action 

 of the wings. The professor also believed it quite 

 possible for a bird to sleep on the wing. In dis- 

 cussing this paper. Professor J. S. Newberry said 

 that he had once shot a bird which came slowly to 

 the ground as if still flying, but reached it dead. 

 He believed that it had died high in the air ; but he 

 had never been able to account for the manner of 

 its descent till now, when he found an explanation 

 in the statement of Professor Trowbridge. 



LEVYING DUTY ON ELECTRICITY. 

 An odd story is told of a customs collector hav- 

 ing vague ideas about electricity. It appears that 

 at St. Stevens, New Brunswick, there is an elec- 

 tric-light station, from which wires are led over the 

 St. John's River to Calais in the States. The 

 collector of customs on the southern side took it 

 into his head that this conveyance of the electric 

 light into his district ought to be charged the same 

 as other commodities. He accordingly sent to the 

 secretary of the treasury to ascertain the amount 

 of duty chargeable on the electricity. This was a 

 poser for the secretary, who, after studying the 

 matter carefully, replied to the officer to the effect 

 " that electricity is not dutiable, being an invisible 

 and subtle agent of power, possessing no substance 

 as a merchantable commodity." In future this 

 mysterious "fluid" may be carried all over the 

 country, notwithstanding the desires of customs 

 officials. 



LABORATORY NOTES. 

 To Prksbkve Rubber Tubing. — Very elastic 

 caoutchouc tubing gradually loses some of its elas- 

 ticity. Later the tubes break on stretching, even 

 if previously laid in warm water; and finally they 

 crack if pressed between the fingers. This change 

 has been attributed to a very slow formation of 

 sulphuric acid by the action of moist air on the 

 sulphur contained in the caoutchouc. By frequent 

 washing with slightly alkaline water, the action of 

 the acid is prevented. Tubes washed five or six 

 times a year remained perfectly elastic. 



Explosion of Ether. — The Moniteur de la 

 Photographit of Paris calls the attention of chem- 



ists to a dangerous explosion of ether which 

 occurred whilst this liquid was being carefully 

 evaporated in a platinum dish, after having served 

 for extracting grease. The ether was very old, 

 having been kept in a stock bottle for many years, 

 and probably exppsed to the light. It contained 

 no less than five per cent of peroxide of hydrogen, to 

 which the explosion is ascribed, and a little acetic 

 and formic acid. 



Explosive Ice. — A most unusual phenomenon, 

 which occurred in the laboratory of the University 

 of Virginia, has been described by Mr. jMallet, the 

 professor of chemistry of that establishment. 

 During a severe frost, ice was formed in the glass 

 vessel of a gazogene, the familiar apparatus for 

 charging water with carbonic-acid gas. The expan- 

 sion of the ice burst the vessel, after which the ice 

 itself exploded repeatedly, and threw off fragments, 

 with a crackling sound. The effect is attributed 

 to the pressure of the gas contained in the ice, 

 which, in the case of water, would appear as 

 simple effervescence. 



Remedy for Frothing in Distillation. — 

 Distillers on a small scale, particularly operators 

 in the laboratory, are often much annoyed by the 

 occurrence of frothing. The pharmacist H . Kun'g 

 has recently proposed a valuable remedy for this. 

 He states that paraffine acts very effectually in 

 preventing the frothing which generally occurs in 

 decomposing ammonia salts by means of lime 

 or magnesia. Two or three grams of paraffine are 

 said to be amply sufficient in this respect for an 

 Ehrlenmeyer flask of eight hundred cubic centi- 

 meters capacity, and containing between two and 

 three hundred cubic centimeters of solution. The 

 same inert substance may be found applicable in a 

 variety of similar cases, and so prevent annoyance 

 and loss to the operator. 



A Current Indicator. — An ingenious indica- 

 tor of excessive currents has been devised by Mr. 

 Crookes. It consists of a flat coil of thin wire 

 painted with a paint of a red color so composed as to 

 change color under heat; around this a screen is 

 placed coated with ordinary red paint of the same 

 shade. Coils of thick wire are placed in parallel 

 circuit with the thin wire coil, and their resistances 

 so adjusted, that, by setting a commutator, the point 

 at which the indication of an excess of current 

 takes place can be varied to suit different require- 

 ments. When a current is passed through the 

 instrument, the thin wire becomes warm ; and when 

 the current is in excess of a definite predetermined 

 quantity, the color changes from red to black. On 

 cooling again, the paint resumes its former hue. 



INDUSTRIAL MEMORANDA. 



A New Iron-smelting Process. — The Brit- 

 ish vice-consul at Moscow reports a new process 

 for producing iron and steel direct from the ore, 

 which has recently been invented and patented by 

 a Russian engineer. The vice-consul says: "The 

 whole secret of the process lies in the construction 

 of the furnace, which is simple and inexpensive. 

 It will be difficult for our iron-masters to believe 

 that, under the new process, iron ore, after sub- 

 mitting it to the ordinary smelting process, is taken 

 direct from the furnace to the rolling-mill, and 

 turned into thin sheets of the finest charcoal iron ; 

 yet such is certainly the case, there being, to my 

 positive knowledge, three such furnaces in this 

 country working with perfect success. There can 

 be but little doubt that the new invention will 

 create quite a revolution in the manufacture of 

 charcoal iron. Whether the process can be applied 

 with equal success where coke is the fuel, I cannot 

 positively assert, as the furnaces I refer to are fired 



with charcoal. I am, however, assured that an 

 experiment has been made with coke, and was 

 crowned with equal success." 



The Action of Nitrogen on Iron. — Mr. H. 

 N. Warren has subjected specimens of fine mer- 

 chant iron to the action of nitrogen in ammonia 

 gas while at a bright-red heat, and found that, on 

 cooling, it showed an intense white surface, with 

 increased hardness. Its fracture was crystalline, 

 and resembled that of siliconized steel. It also 

 showed the presence of nitrogen under analysis, 

 through the formation of ammonia. Copper bars 

 also showed similar changes when subjected to 

 nitrogen in the same way. Some of the bars split 

 up on being brought into the atmosphere before 

 they were cold. Mr. Warren thinks this phenom- 

 enon due to their absorption of ammonia while 

 heated, and expulsion of it when cooled, — an effect 

 similar to the absorption of oxygen by silver. 



Iron-Brick Paving Stones. — Paving blocks 

 called iron-brick are now being introduced in 

 Germany. This brick is made by mixing equal 

 parts of finely ground red argillaceous slate and 

 finely ground clay, and adding five per cent of iron 

 ore. This mixture is moistened with a solution of 

 twenty-five per cent sulphate of iron, to which fine 

 iron ore is added until it shows a consistency of 38° 

 Baumd. It is then formed in a press, dried, dipped 

 once more in a nearly concentrated solution of sul- 

 phate of iron and finely ground iron ore, and is 

 baked in an oven for forty-eight hours in an oxidiz- 

 ing flame and twenty-four hours in a reducing 

 flame. The German government testing laboratory 

 for building-materials has reported favorably on 

 this brick. 



To Repair Stonework. — Make a paste of 

 silicate of potash and hydraulic cement, and add 

 half its weight of very fine sand. This adheres 

 perfectly to stonework, and soon becomes very hard 

 and durable. It is especially applicable to stone 

 steps which have become worn from use. 



Salt-Water for Cement Mortar in Ger- 

 many. — German experiments designed to ascer- 

 tain the effect of frost upon hydraulic mortars and 

 cements gauged with and without the addition of 

 salt to the water have been quoted in the Revue 

 Industrielle. Cubes of stone six cubic centimeters 

 in area were used in these experiments, and were 

 joined together with cement mixed with water 

 ranging from pure rain-water to water containing 

 from two to eight per cent of salt. While the 

 cement was yet fresh, the blocks were exposed in 

 air at a temperature of 20° to 32° P., after which 

 they were kept for seven days in a warm room. At 

 the end of this time the specimens were examined. 

 The cement made with pure water was quite 

 crumbled, and had lost all its tenacity. The 

 cement mixed with water containing two percent 

 of salt was in better condition, but could not be 

 described as good ; while that containing eight per 

 cent of salt had not suffered from its exposure to 

 the low temperature. 



Cheap Method of Platinizing Metals. — In 

 this new process the metallic object is covered with 

 a mixture of borate of lead, oxide of copper, and 

 spirits of turpentine, and submitted to a tempera- 

 ture of from 250° to 330°. This deposit, upon 

 melting, spreads in a uniform layer over the object. 

 Then a second coat is laid on, consisting of borate 

 of lead, oxide of copper, and oil of lavender. Next, 

 by means of a brush, the object is covered with a 

 solution of chloride of platinum, which is finally 

 evaporated at a temperature of not more than 200°. 

 The platinum adheres firmly to the surface, and 

 exhibits a brilliant aspect. If the deposit be made 

 upon the first coat, the platinum will have a dead ^ 

 appearance. Platinizing in this way costs, it is 

 said, about one-tenth the price of nickel plating. 



