July 15, 1892.] 



SCIENCE. 



33 



tempted ? Should any part of the laboratory practice be classified 

 as shop work, and so named, unless articles are made for sale ? 

 Should anything be introduced that should be called "shop work?" 

 Should that portion of the laboratory embracing the manual ele- 

 ment be classified as " shop," " school shop," " work shop," etc., 

 ■or elementary mechanical laboratory ? Should the more advanced 

 portion embracing testing of various kinds be classified in such 

 way as advanced mechanical laboratory, testing laboratory, etc. ? 

 It is further suggested that particular attention be given to the 

 number of hours devoted to a subject, and the ground covered ; 

 the method of instruction, i.e., whether by lecture, recitation or 

 practice, separately or combined. The address of the secretary is, 

 A. J. Wiechardt, South Bethlehem, Pa. 



— The North Cai-olina Experiment Station has distributed a 

 large quantity of broom-corn seed and instructions as to its culti- 

 vation to alliancemen and others, with a view to establishing it 

 among the profitable crops in places well adapted for its best de- 

 velopment. Close planting on fairly rich land is required for a 

 good crop of brush fitted for making fine brooms. In order to 

 better assist those who desire to learn all they can of this crop, 

 and that all may have the benefit of as much information as pos- 

 sible on the subject of growing broom-corn and making brooms, 

 the Experiment Station will engage to supply as many as wish a 

 copy of "Broom-Corn and Brooms," a small book published by 

 Orange Judd Co. of New York, at the wholesale price, with the 

 postage added. The usual price is 50 cents. Send 30 cents in 

 silver or stamps to the Experiment Station at Raleigh, if you wish 

 a copy of this little book. 



— A paper upon the oxidation of nitrogen by means of electric 

 sparks is contributed, by Dr. V. Lepel, to the current number of 

 the Annalen der Physik mid Chemie. It is well known that small 

 quantities of nitric and nitrous acids and their ammonium salts are 

 produced during the passage of high-tension electrical discharges 

 through moist air. Dr. V. Lepel's experiments, according to 

 Nature, have been conducted with the view of obtaining more 

 precise information concerning the nature of the chemical reac- 

 tions which occur, and the experimental conditions most favorable 

 for increasing the amount of combination. The first action of the 

 spark discharge appears to be the production of nitric oxide, which 

 is immediately converted by the oxygen pi-esent into nitrogen 

 peroxide. The latter then reacts with the aqueous vapor present, 

 forming nitric acid and liberating nitric oxide in accordance with 

 the well-known equation 3NO„ f H^O = 2HNO3 -I- NO. It has 

 been found, however, that the continued passage of sparks through 

 the same quantity of moist air does not result, as might at first 

 sight be expected, in the conversion of more and more of the 

 atmospheric gases into oxidized products. For the passage of 

 sparks through the gaseous oxides of nitrogen first formed results 

 in their decomposition again into their elementary constituents. 

 If, for instance, spark discharges are passing at the rate of one per 

 second, the whole of the nitrogen peroxide molecules have not 

 time to react with the water molecules to form nitric acid, before 

 the passage of the next spark, and hence some of them suffer de- 

 composition; indeed, it is probable that a number of the nitric 

 oxide molecules first formed have not even time to combine with 

 ■oxygen to form the peroxide before the passage of the next dis- 

 charge, which brings about their dissociation. Hence it is, that, 

 in a closed space, a limit is soon reached beyond which there is no 

 further increase in the amount of nitric acid. For this reason the 

 yield of nitric acid has hitherto been very small. Dr. V. Lepel 

 has made experiments, therefore, with a slowly-moving atmos- 

 phere, and under different conditions of pressure, and with various 

 types of spark discharge, with the result that he has already in- 

 creased the amount of combination to 10 per cent of the total 

 amount of air employed. The air is exposed under increased 

 pressure to a series of parallel spark discharges in the same tube. 

 The change of atmosphere is not made continuously, but inter- 

 mittently, and the gases are expelled from the discharge tube into 

 a large absorption vessel, in which the products are absorbed in a 

 solution of water, or of a caustic alkali. Detailed accounts are 

 given in the memoir of the eflicacy of the various forms of high- 

 Aension discharge, and Dr. V. Lepel is now experimenting with 



the di- charge from a Topler influence machine with sixty-six 

 rotating plates. Of particular interest are his remarks concerning 

 the probable effect of the high-voltage discharges of which we 

 have lately heard so much. He considers it not improbable that 

 by their aid a new mode of producing nitric acid from the atmos- 

 pheric gases on the large scale may be introduced, rendering us 

 altogether independent of the natural nitrates as a source of nitric 

 acid. 



— According to the Pioneer Mail of June 8, the residents of 

 Howrali have been finding lately that jackals are animals of any- 

 thing but an attractive temper. In some cases they have come 

 right up to the bungalows in search of prey. A little girl, aged 

 about five years, was playing in a verandah, when a jackal sud- 

 denly rushed on her, and was dragging her away, when she was 

 rescued. She was severely bitten. Three natives, while walk- 

 ing along the Kooroot Road, were attacked by a jackal, which 

 was only driven off after a stubborn fight; and a tale is told of 

 two women, while standing near a tank, being attacked and bit- 

 ten. So serious has the state of matters become that the public 

 propose to submit a memorial to the district magistrate praying 

 for the adoption of measures for the destruction of these pests. 



— C. Creighton. in a letter to Nature, June 30, on the immu- 

 nity of the African negro from yellow fever, says: " This point, 

 interesting to anthropologists, is raised anew by a writer on the 

 history of epidemics {Nature June 16), who asks whether the al- 

 leged protection is supported by all recent authorities. Recent 

 authorities are not so well placed forjudging of this matter as the 

 earlier ; for the reason that immunity is not alleged except for 

 the African negro of pure blood or unchanged racial characters, 

 and that these conditions of the problem have been much less 

 frequently satisfied in the yellow fever harbors of the western 

 hemisphere since the African slave trade ceased. However, there 

 was a good opportunity in 1866, during the disastrous yellow fever 

 among the French troops of the Mexican expedition when they 

 lay at Vera Cruz. Among them was a regiment of Nubians, who 

 had been enlisted for the expedition by permission of the Khedive : 

 that regiment had not a single case of yellow fever all through 

 the epidemic. The African negro regiment brought over from 

 the French colonies of Martinique and Guadeloupe had two or 

 three cases, with, I think, one death. The rest of the troops, in- 

 cluding Frenchmen, Arabs from Algeria, native Mexicans and 

 Creoles, had no immunity whatever, but, on the other hand, a 

 most disastrous fatality. The medical officers of the French ser- 

 vice have recorded the facts principally in the Archives de Mede- 

 cine Navale, their conclusion as to racial immunity being the 

 same that has passed current among the earlier authorities as a 

 truth of high general value (admitting, of course, of exceptions in 

 special circumstances), and a truth that has never, so far as I 

 know, been formally controverted by anyone, although other 

 points concerning yellow fever have been the subject of as obsti- 

 nate controversy as those touching small-pox itself. The experi- 

 ences of the French at Goree, a town with ten times as many ne- 

 groes as whites, exactly confirmed those of Vera Cruz in the 

 same year {Arch, de Med. nav., ix., 343). The immunity of the 

 African negro from yellow fever has become a paragraph in some 

 anthropological text-books. It is from the anthropologists, and 

 not from medical authorities, that Darwin cites the fact in his 

 " Descent of Man," adding an original theory of the immunity, 

 which he was unable to establish after much inquiry. His theory, 

 I need hardly say, was not that "negroes in infancy may have 

 passed through some disease too slight to be recognized as yellow 

 fever," — whatever that may mean — " but which seems to con- 

 fer immunity." The theory, however, is another story, or 

 "another volume," as the writer just cited is pleased to suggest; 

 and as for the historical fact of immunity, no one denies it. unless 

 it be Dr. Pye Smith in his recent Lumleian lectures {Lancet, 

 April 23. 1893, p. 901), who gives no reasons. It is unfortunate 

 that the anthropologists (Darwin among them) should have intro- 

 duced one element of dubiety in placing mulattoes on the same 

 footing, in respect of immunity, as negroes of pure descent, and 

 another in mixing up malarial or climatic fevers with yellow 

 fever." 



