March 11, 1887.] 



8GIENCE. 



227 



Welle, Naclitigal was the first to give some new 

 information. In 1875 he published a map from 

 his surveys and from information obtained in 

 Dar For and Wadai. Junker explored, in 1876 

 and 1877, the western tributaries of the Bahr-el- 

 Abiad. In the same years a Greek physician, 

 Panagiotes Potagos, travelled over a great part 

 of the district. As, however, he made no astro- 

 nomical observations, and his itinerary is very 

 primitive, the results of his journey are not reli- 

 able. This is still more the case with Bohndorff's 

 journeys. This man, a goldsmith, who had been 

 in the service of General Gordon, travelled in the 

 region of the head waters of the Welle. Later 

 on, when Junker started on his second journey, 

 he took Bohndorff for his servant, and in Janu- 

 ary, 1880, they left Khartum. The first summer 

 was spent in the Niam-Niam country, and since 

 that time Junker has travelled in Mombuttu and 

 in the district of the Welle and the other rivers 

 running west. Lupton Bey and his agents made 

 many important journeys, the expedition of Rafai 

 Aga being of particular interest. He is said to 

 have reached the lake on the Lokoi. The north- 

 western tributaries of the Bungu, as shown on the 

 sketch-map, are from Flegel's reports, who learned 

 about them on his journey in Adamaua. The cen- 

 tral part between the regions traversed by Flegel, 

 Nachtigal, and Junker, is still totally unknown. 



THE HEALTH OF NEW YORK DURING 

 JANUARY. 



The population of New York City at the be- 

 ginning of 1887 may be approximately stated to 

 have been 1,461,466. The deaths during the month 

 of January from all causes vs^ere 3,507, which is 

 but 5 more than during the preceding month, 

 although the population was greater by more than 

 3,000. Of this number, 140 died on the 5th, the 

 greatest mortality of the month (see page 228). 

 Diarrhoeal diseases caused 48 deaths, a reduction 

 of 17 as compared with December, and the lowest 

 mortality from this cause since March, 1886. The 

 deaths of children under five years of age amount- 

 ed to 1,523, differing but little from the preceding 

 month. Consumption caused 524, diphtheria 204, 

 and scarlet-fever but 46 deaths. The mortality 

 from the last-named disease was double that of 

 December. In November there were recorded 166 

 deaths as due to measles. In December this in- 

 creased to 271, and in January the mortality rose 

 to 294, exceeding by no inconsiderable figure the 

 combined deaths from diphtheria and scarlet- 

 fever, emphasizing, what we have already di- 

 rected attention to, that measles is not a trivial 

 disease, but one in regard to which all precautions 



relating to isolation and disinfection should be 

 promptly and thoroughly taken and maintained. 



The maximum temperature of the month, 62° F., 

 was reached at 4 P.M. on the 23d. This was 

 nearly ten degrees above the average for the past 

 ten years. The lowest point reached by the mer- 

 cury was 4° F., at 12 p.m. on the 18th, and again 

 on the 19th at 2 a.m. The average for the decade 

 is 3.1" F., although during the same month of 

 1879 it fell to —4° F., and in 1882 to —6° F. The 

 rainfall for January was 4.42 inches, included in 

 which are 6.625 inches of snow. The average rain- 

 fall for this month for the ten years commencing 

 1878 is 3.82 inches, so that more than the average 

 fell during January. The largest amount of snow 

 which fell during this period in the same month 

 was 17.5 inches, in the year 1882. Since then, in 

 but one year, 1885, has less snow fallen than dur- 

 ing January of 1887 : the average has been nearly 

 10 inches. There were four snow-storms during 

 the month. In that which occurred on the 5th 

 and 6th, 2 inches fell ; that of the 9th and 10th 

 resulted in a fall of 4 inches ; while the others 

 were insignificant. 



GEOGRAPHICAL NOTES. 

 Africa. 



Dr. Hans Schinz gives the following report of 

 the present state of Lake Ngami. The lake has 

 not dried up, but is gradually decreasing in size. 

 The Okavango, or Ombuenge, forms, north-west 

 of the lake, an extensive swamp, and during the 

 dry season the lake receives only a small quantity 

 of water from it. During the rainy season, how- 

 ever, the small brooks swell up and form a large 

 stream, which empties itself into the lake. The 

 Tamulakan, which branches off from the Om- 

 buenge in latitude 18° 40' S., empties itself into 

 the Botelet, not into the Zambezi. 



Gottl. Ad. Krause has succeeded in entering the 

 territory south of Timbuktu. Since Barth's ex- 

 pedition in 1853, no white man has visited this 

 district. On the 7th of July, KJrause left the large 

 city of Salaga on the Volta, and later on reached 

 Mosi, whence he started on Oct. 26 for Timbuktu. 

 The district through which he has travelled has 

 been known only through information obtained 

 by Barth. Our knowledge of the district between 

 the fabulous Kong Mountains and the most north- 

 ern part of the Niger is still extremely imperfect, 

 being founded only on information obtained from 

 natives. 



Under the auspices of the secretary of state of 

 France, Camille Douls is going to explore the Wad 

 Draa, which empties itself near Cape Noon. This 

 periodical river runs at some distance along the 



