Fed. 24, 1 88 7] 



NATURE 



403 



an intelligent man, and even finds time in the midst of his ivory 

 raids to attend to the interests of science. He recently came 

 upon a remarkable tribe on the Congo, to the north of Nyangwc-, 

 who do a great deal of work in copper, and whose inlaid work 

 ill that metal is of a highly artistic character. He sent several 

 specimens to an English friend at Zanzibar, who has brought 

 ■ liem with him to this country. Still more interesting is the dis- 

 ■very by Tippoo, among the same people, of what may be 

 icjjarded as the first steps towards a currency. Spears are 

 riaturally among the most valuable articles which such a people 

 possess, and, as a matter of fact, the value of everything is reckoned 

 by them in terms of spears. Not only so, but they have actually 

 reached the stage of a conventional currency. Enormous spear- 

 heads of very thin copper are made, some six feet in length, 

 which are passed from hand to hand, just as banknotes are with 

 us. These spears, for e.xaraple, in the purchase of ivory, are 

 valued at ;^200 — their intrinsic value being probably not so many 

 pence. We are glad to know that a specimen is likely to be 

 deposited in the British Museum. Readers of Schweinfurth's 

 " Ileart of Africa" will remember that among the Niam-Niams 

 hoes are used for a similar puqjose, only after a reverse fashion ; 

 tmy hoes, what we should call mere toys, are in common use as 

 money. 



The principal article in the new number of Pdermarin' s 

 MitteiUingai is a summary of the journey across Africa from 

 Mossamedes to Quillimane, by the Poituguese travellers, MM. 

 Capello and Ivens in 1SS4-85. The most valuable geographical 

 work accomplished by the travellers was the exploration of the 

 interesting region lying between the Upper Zambesi and Lake 

 Bangweolo. The important north-east tributary of the Zambesi, 

 'he Kabonipo, was traced to its source in the closest pro.\imity to 

 liesourccsof the Lualaba, one of themost important contributories 

 ' I the Congo. From here a zigzag was made eastwards and south- 

 wards, across the head-waters of many affluents of the Zambesi, 

 until that river was reached about 16' S. and 29" E. MM. 

 Capello and Ivens took veiy numerous astronomical and meteoro- 

 logical observations during their journey, as well as observations 

 for terrestrial magnetism. The complete narrative of the journey, 

 with ami)le supply of maps and scientific appendixes, has just 

 been published in Portuguese. The same number of the Milldl- 

 iingcn contains a large collection of barometric data on the 

 hypsometr}' of South America, mainly Pent and Bolivia. 



Prof. L. Bodio sends to the Bolktlino of the Italian Geo- 

 _;raphical Society for December 1S86 an important paper on 

 Italian emigration, which he divides into two categories — 

 permanent and temporary. The latter, which is essentially of a 

 periodical character, varies from So, 000 to 100,000 persons yearly, 

 and consists chiefly of stonemasons, bricklayers, navvies, and 

 other day-labourers from the northern provinces of Piedmont, 

 Lombardy, and Venice, who seek casual employment on the 

 public works in .Austria, France, Germany, Switzerland, Corsica, 

 and elsewhere. They generally leave their homes in the spring, 

 returning with their earnings towards the clise of autumn, and 

 enjoy the reputation of sober, steady, intelligent workmen. The 

 permanent movement, which alone constitutes emigration pro- 

 perly so called, h.is already risen during the last twenty years 

 Iroin less than 20,000 to about So.ooD annually, and is directtd 

 from the same northern provinces, and from Liguria and parts of 

 Naples, almost exclusively to the Argentine States and some 

 other parts of the New World. The emigrants, who sail either 

 directly from Genoa, Naples, and Palermo, or from the French 

 ports of Marseilles, Bordeaux, anl Havre, comprise between 

 60 and So per cent, of male adults, the small minority consisting 

 of women and children. They represent nearly all social con- 

 ditions, the peasant class, however, largely predominating in 

 South -America. For the year 1885 the returns show 57,827 to 

 the Argentine Republic ; 15,48510 the United States; 12,311 

 to Brazil ; and 1477 to Uruguay. The chief inducements to 

 leave their native land and settle abroad appear to be poverty, the 

 desire to better their fortunes, and the direct encouragement of 

 ftiends and relatives who have prospered in their new homes 

 across the .Atlantic. Very few ever return to reside permanently 

 in the mother country. 



Thh Germans are losing no time in making themselves 

 acquainted ^^ ith the section of New Guinea which they have 

 annexed. The Empress .Augusta River, close to the western 

 boundary of the German territory, was recently navigated by 

 Admiral von Schlcinilz and Dr. Schrader, in the steamer Otiilie, 

 for a distance of 224 miles. It being the dry season, the river 



was too shallow for further navigation by the steamer. The 

 ship's steam-launch, however, proceeded 112 miles further, to a 

 point situated in 4' 16' S. and 141° 50' E. ; judging from the 

 quantity of water in the river the voyage could have been con- 

 tinued 50 miles further, but fuel ran short. For over 200 miles 

 from its mouth the river flows through extensive plains ; then its 

 course suddenly changes, and it assumes the character of a 

 mountain stream, forcing its way through hills of gneiss, mica- 

 slate, and quartz ; but the velocity of its current remains uniform. 

 The settlements on its banks were only found at long intervals. 



OK THE CONSTITUTION OF THE NITRO- 

 GENOUS ORGANIC MA TTER OF SOILS 

 T^HE organic matter of soils, the residue of the limited oxida- 

 •^ tion of vegetable and animal matter, has a,ipeared a subject 

 so complex and obscure, and promising the investigator so little 

 of definite result, that it has received but scanty attention. The 

 researches made have been chiefly confined to a study of tlie 

 non-nitrogenous humic acids, the nitrogenous organic bodies 

 present in soil have been scarcely at all investigated. The 

 agricultural chemi-t has indeed not unfrequently spoken and 

 written as if such investigation was superfluous, holding that the 

 nitrogenous organic bodies contained in humus were not capable 

 of serving as food for farm crops until they had undergone a 

 further change into ammonia, and finally into nitric acid. A 

 valuable paper, " Sur les principes azotes de la terre vegetale," 

 by Berthelot and Andre, which ajipeared in the Comptes 

 ritidiis of December 6, has called attention to this neglected 

 subject, and has done much to clear up our ideas 

 respecting the constitution of the nitrogenous organic matter 

 contained in soils. Like many other epoch-making treatises, 

 the paper in question brings forward facts which have, in part, 

 been already established by earlier investigators ; but in no 

 earlier investigation, as far as I am aware, have the facts ap- 

 peared in such a striking aspect, nor have the conclusions which 

 flow fr.jm them been clearly set forth. 



Berthelot and Andre conclude that the nitrogenous matter of 

 soils is mainly composed of insoluble amides ; ^ these amides 

 are decomposable by the action of acids, alkalies, and to a less 

 e.xtent by water, into ammonia and soluble amides (amido-acids), 

 in the same manner as other bodies of the same class with which 

 the chemist is already quite familiar. The behaviour of soil 

 towards hydrochloric acid furnishes the main facts on which the 

 French chemists base their conclusions. They find that when 

 a soil tolerably rich in nitrogen (0174 per cent.) is treated with 

 dilute hydrochloric acid, a quantity of ammonia is found in the 

 solution, which is greater as the strength of the acid is in- 

 creased, as the time of its action is lengthened, and especially 

 as the temperature is raised ; two hours' boiling produces, in 

 fact, with various strengths of acid, four, five, and six times as 

 much ammonia as five days' action in the cold. Besides ammonia, 

 there is found in the acid solution a considerable quantity of 

 some nitrogenous organic body, the amount of which rises and 

 falls with the quantity of the ammonia. In cases in which the 

 action of the acid was carried farthest, the nitrogen of the 

 solulile organic body bore to the nitrogen of the ammonia a 

 proportion of about 3 to I. The extent to which the nitroge- 

 nous matter of the soil was attacked by the hydrochloric acid 

 was very considerable ; boiling 200 grammes of soil for two hours 

 with 400 cubic centimetres of water, and 100 cubic centimetres of 

 strong hydrochloric acid, resulted in the solution of 31 '8 per 

 cent, of the soil nitrogen, and the conversion of 7'I per cent, of 

 it into ammonia. The nature of the nitrogenous organic matter 

 found in solution in the hydrochloric acid has apparently not 

 been particularly investigated by Berthelot and Andre, but the 

 whole reaction is so characteristic of the splitting up of an amide 

 that their view of the constitution of this body becomes highly 

 probable. 



Investigations earlier than those of Berthelot had shown that 

 hydrochloric acid dissolves nitrogenous matter from the soil. 

 Loges has pointed out that this solution contains a nitrogenous 

 body precipitable by phospho-tungstic acid. The nitrogen and 

 carbon in this precipitate had a relation of about I to 6 '2. My 

 own experiments show that a nitrogenous body precipitable 

 by phospho-tungstic acid is also extracted from soil by a cold 



' Tlie presence of amides in soil was long ago inferred by S. W. Johnsor 

 ('• How Crops Feed," p. 247), from the reactions of soil with which chemists 

 were then acquainted. 



