/an. 29, 1880] 



NATURE 



3" 



supposed. In the southwest are long bands of sand, not ex- 

 ceeding eight days' march in width. Adrar-Temar, the country 

 of the travellers, is placed like a long and narrow island between 

 two of these bands of sand. It is an almost level region, slightly 

 elevated above the sands, which tend to encroach upon its 

 borders. Intermittent streams are found in the country, and 

 there are numerous towns or large villages, containing a consi- 

 derable population. The three pilgrims represent their country 

 as covered with gum-acacias, and ostriches greatly abound. The 

 most important commercial fact in connection with Adrar is the 

 existence at Ijil of an immense deposit of rock silt, which, as 

 we advance towards the country of the negroes becomes the 

 most valuable article of trade. Tichu (? Tishit), some days' journey 

 to the south-east of Ijil, is the principal market for the trade in 

 salt, for which slaves arc the principal exchange. 



Herr Clemens Denhardt, who has just returned to 

 Germany from an exploring tour in Eastern Central Africa, has 

 received a grant of 500 marks (20/.) from the Gesellschaft f iir 

 Erdkunde, at Berlin, to defray the cost of publishing his notes of 

 travel. 



M. Grandidier, the explorer of Madagascar, has been ap- 

 pointed president of the governing body (Section Centrale) of 

 the Paris Geographical Society for 1879. Admiral La Ronciere 

 Le Nourry has been continued president of the Society. The 

 Geographical Society of Paris is preparing to hold a reception 

 when Prof. Nordenskjold arrives in France ; but' the first step 

 will be taken by the Society of Marseilles, the city at which 

 Nordenskjold will land from Naples, according to all probability. 



We learn from the last number of the Isvcstia of the Russian 

 Geographical Society that the expedition of M. Pyevtsoff to 

 Mongolia was very successful. M. Pyevtsoff, after having 

 stayed seven days at Koukou-khoto, started for Kalgan (in the 

 south-east part of the Gobi steppe) where he remained for two 

 months, studying the trade of China with Mongolia. Thence 

 the expedition went to Urga, and from Urga to Ulassoutai, 

 following thus a route which never was before explored. From 

 Ulassoutai M. Pyevtsoff turned west to the Chuyra river, which 

 was reached at Kosh-agach ; this route was quite unknown until 

 now. On the whole thousand miles' distance between Urga and 

 Kosh-agach the expedition made a survey, and M. Pyevtsoff 

 determined the latitudes and longitudes of twelve points. On 

 the whole the expedition has made, on its way from Khobdo to 

 Kalgan and thence to Kosh-agach, no less than 2, 700 miles of 

 surveys, and determined astronomically the position of twenty- 

 six points, all longitudes being determined as well by chrono- 

 meters as by the occultations of stars. Barometrical measure- 

 ments were made during the whole journey, and very rich 

 zoological, botanical, and mineralogical collections were obtained. 



The St. Petersburg Geographical. Society has received news 

 from Col. Prjvalsky, vid Pekin. The intrepid traveller has safely 

 arrived at Zaidam, on the Tibetian frontier, after having crossed 

 the hitherto unknown country from Hami vid Shatsheu to 

 Zaidam. From the latter place he will proceed to the interior 

 of Tibet. News has also been received from the chief of the so- 

 called Samara Expedition, referring to the readiness of the 

 Chiwinz tribe to restore the old course of the Amu Darya by 

 destroying the dykes on the lower part of the river. The expe- 

 dition sent out by the Russian Government Office for Communi- 

 cations, under Col. Gluchowski, and charged with the investiga- 

 tion of the lower course of the Amu Darya, w ith a view to 

 rendering it navigable in future, also begins to show signs of 

 activity. 



The " Karl Stangen'sche Reisebureau," at Berlin, will publish a 

 description of its first journey round the world (1S78-79) early 

 in March, this description to serve as a guide for future journeys 

 and intending tourists. 



THE EFFECTS OF UNINTERRUPTED SUN- 

 LIGHT ON PLANTS 



pROF. SCHUBELER of Christiania, who for nearly 

 ■*■ thirty years has been engaged in observing the influence 

 exerted by differences of climate on vegetation, has published 

 the result of his observations in recent numbers of our 

 Norwegian namesake, Natttrcn. The first of the series of 

 his observations, which he has given in detail, refer to winter- 

 wheat, and were undertaken with the special view of noting 



what effect the almost unbroken sunlight of the short Scandi- 

 navian summers bad on plants raised from foreign seed. The 

 experiments were made with samples of grain from Bessarabia 

 and Obi' >, and in both cases it was found that the original colour of 

 the grain giadually acquired each year a richer and darker colour 

 — the difference being perceptible even in the first year's crop — 

 until it finally assumed the yellow-brow n tint of other home- 

 grown Norwegian winter-wheats. Similar results were obtained 

 with maize, different kinds of garden and field peas and beans, 

 and certain other garden plants, as celery, parsley, &c. In no 

 case has Dr. Schubeler found that an imported plant, capable of 

 being cultivated in Norway, loses in intensity of colour after 

 continued cultivation ; while in regard to many of the common 

 garden flowers of Central Europe, he believes it may be asserted 

 with certainty, that after their acclimatisation in Norway, they 

 acquire an increase of size, as well as an augmentation of colour. 

 These altered conditions are more forcibly manifested the further 

 north we go, within the limits of capacity of vegetation for 

 different plants. Thus it has been observed by Prof. Wahlberg 

 of Stockholm, that Epi'obium angtisti folium, Lychnis sylvestris, 

 Geranium sylvaticum, and many other plants common to 

 Lapmark and the more southern districts of Sweden, attain in 

 the former a size and brilliancy of tint unknown in the latter. 

 The change in the case of Veronica serpyllifolia and Trientalis 

 europaa is remarkable ; the former changing as it goes further 

 north from a pale to a dark blue, and the latter from white to 

 rose-pink. It is noteworthy that a tinge of red is a common 

 characteristic of the vegetation of the Scandinavian Fjselds ; 

 this being observable alike in blue, yellow, green, and white 

 colours. 



Colour is not, however, the only property affected by the 

 unbroken continuance of daylight in the summers of Scandinavia, 

 for according to Dr. Schubeler, the aroma of all wild and 

 cultivated fruits, capable of cultivation in the northern lands, is 

 much greater than that of the same fruits when grown in more 

 southern countries. This is especially observable in regard to 

 strawberries, cherries, and the various kinds of wild marsh and 

 wood berries. In corroboration of this, Prof. Fluckiger of Strass- 

 burg has found that the Norwegian juniper yields a much larger 

 amount of essential cil than can be obtained from the shrub 

 when grown in Central Europe. This excess of aroma in 

 northern plants and fruits co-exists with an inferior degree of 

 sweetness ; thus the commen golden-drop plum, and the green- 

 gage of Christiania, or Throndhjem, although large, well- 

 coloured, and rich in aroma, are so deficient in sweetness as to 

 seem unripe to those who have eaten these fruits in France, or 

 Southern Germany. 



Dr. Edmond Goze, who has long been resident at Coimbra, 

 informs Dr. Schubeler, that his observations on the fruits of 

 Portugal enable him to corroborate that observer's opinion in 

 regard to the different conditions on which aroma and sweetness 

 respectively depend. The strawberries grown in large numbers 

 near Coimbra are, he says, of great size, extremely sweet, but 

 almost wholly deficient in aroma and flavour. The same remark 

 refers to the Portuguese wines, when compared with the highly 

 flavoured yields of the Rhenish and other northern vineyards ; 

 and a consideration of these varying conditions leads him to 

 accept as an established fact, that light bears the same relation 

 to aroma, as heat does to sweetness. 



This increase of aroma, or intensification of flavour, due to 

 the uninterrupted action of the sun's light, has the effect of 

 makin" some of our most savoury garden plants almost uneatable 

 in Scandinavia. Thus Dr. Schubeler has found that common 

 white stick-celery, which had been grown near Christiania with 

 careful attention to the methods followed in England, and 

 which in outward appearance could not be distinguished from 

 plants brought direct from Covent Garden Market, had a sharp 

 unpleasant taste, when compared with the milder and more 

 agreeably flavoured English plants. The same result was 

 observed in garlick, shalots, and onions, and although it must be 

 admitted that as the expressions of mere individual taste, the 

 writer's conclusions in regard to this point are open to doubt, it 

 should at the same time be borne in mind that they are based on 

 practical observations and experiments, continued for nearly 

 thirty years, and confirmed by the concurrent testimony of 

 several of his colleagues, who, like himself, were desirous of 

 deducing practical results from the acclimatisation of plants in 

 Norway. From this point of view, some of Dr. Schubeler's 

 observations are especially interesting, and in the present low 

 condition of Norwegian industrial development, their practical 



