August i, 1890.] 



SCIENCE. 



minimum barometer, and a minimum during the morning mini- 

 mum barometer, these being probably intimately connected with 

 the diurnal ascending and descending currents of the atmosphere. 

 Interesting intimate relations are also indicated between the num- 

 bers of dust-particles and the cyclones and anticyclones over 

 north-western Europe at the time. The observations also indicate 

 that the dust-particles may vary enormously during the presence 

 of mist or fog, without being accompanied by any difference in 

 the apparent density of the fog. The council consider that the' 

 inquiry is an extremely hopeful one; and, in view of the relations 

 with cyclones and anticyclones, its bearings as regards the fore- 

 casts of the weather will be very specially investigated. 



— For several years past it has been the practice of the Indian 

 Meteorological Department to issue in the month of June a fore- 

 cast of the prospects of the monsoon rains, based partly on the 

 reported extent and thickness of the Himalayan snows, partly on 

 the distribution of the atmospheric pressure, the small variations 

 of which are found by experience to be remarkably persistent in 

 India, and to serve as an indication of the probable strength of the 

 monsoon, and alternately of the prevalence of dry land winds. 

 The forecast for the forthcoming season announces, according to 

 Nature of July 17, that owing to the very slight snowfall of 

 Afghanistan, Baluchistan, and almost the whole of the Himalayan 

 region, the conditions are eminently favorable for a good strong 

 monsoon. The only unfavorable indication is that the winter of 

 1889 has been very severe in Yarkand, and perhaps in other dis- 

 tant parts of central Asia. The pressure is unusually low this year 

 in Bengal, and above the average in central India and the northern 

 half of Bombay ; and the local pressure conditions considerably 

 resemble those of 1876. It is therefore considered probable, that 

 while the eastern half of the Ganges valley, Assam, and Burmah 

 will receive early and abundant rain, the rains may be late and 

 scanty over a considerable area of north-western India. 



— Recently Mr. S. F. Menage of Minneapolis very liberally 

 agreed to fit out a scientitic expedition to the Philippine Islands. 

 Messrs. D. C. Worcester and F. S. Bournes of the University of 

 Michigan were willing to go, and on July 32 they left Minneapolis 

 for Vancouver's Island, en route to Manila. They purpose remain- 

 ing in the Archipelago for at least two years, and during that 

 time they will prosecute the work of zoological and botanical col- 

 lecting under the most favorable auspices. While specializing 

 upon birds and corals, they will not limit themselves to these, but 

 intend to make collections of Entomostraca, fungi, fresh-water 

 Algce, Mammalia, and flowering plants. They will give some 

 special attention, moreover, to the land-shells of the islands, many 

 of which present most curious problems of descent and distribu- 

 tion. The large collections which will be made, if no unforeseen 

 accidents occur, are to be worked over under the auspices of the 

 Minnesota Academy of Sciences, and will be deposited in its 

 museums for the use of scientific men. Both Mr. Worcester and 

 Mr. Bournes are experienced zoologists, and Mr. Worcester was 

 for some time instructor of botany in the University of Michigan: 

 so they are well qualified to undertake the study of so diverse and 

 little known a fauna and flora as that of the Philippine Islands. 

 The thanks of American botanists and zoologists are due Mr. S. F. 

 Menage, who so generously endowed the expedition. From it re- 

 sults of real scientific value may be confidently expected. 



— That the latitude of a place is not constant has long been 

 suspected ; but it was only at the end of last year that systematic 

 observations, carried out at some of the observatories of central 

 Europe, clearly established the fact by eliminating all chances of 

 error in instruments and observers. Professor Helmert reported 

 in No. 2,963 of the Astronomische Nachrichten that the latitudes 

 of Berlin and Potsdam, which had shown no perceptible variation 

 during the first six months of 1889, in the third quarter of that 

 year increased at first, and then diminished, the movement con- 

 tinuing till January, 1890. In Berlin and Potsdam this decrease 

 amounted to from five to six inches, and this variation was con- 

 firmed by observations at Prague and Strasbourg, the results at 

 the first three observatories agreeing to within one-tenth of a 

 second. According to The Scottish Geographical Magazine, the 

 subject is to be discussed at the meeting of the Commission for In- 



ternational Geodesy, to be held in Freibm-g next September, when, 

 it is to be hoped, arrangements will be made for a strict examina- 

 tion of this phenomenon. 



— The population of Iceland has for several years been decreas- 

 ing, owing to the strong tide of emigration to America. It is 

 stated in The Scottish Geographical Magazine that the population 

 in 1888 was 69,224, whereas in the preceding year it amounted to 

 69,641, and in 1885 to 71,613. This phenomenon is most marked 

 in the northern and eastern parts of the island. The growth of 

 the population of Reykjavik, the capital, from 3,460 in 1885 to 

 3,599 in 1888, shows that the tendency of population to concen- 

 tration in towns prevails also in Iceland. 



— Many of the workmen who were employed in the caissons of 

 the East River, Forth, and other bridges, sufl'ered severely from 

 the effects of working in an atmosphere of compressed air, as do 

 those now employed in the tunnel under the Hudson River. Dur- 

 ing the construction of the Forth Bridge piers, it was noticed that 

 the sufferers were in the habit of spending their Sundays and 

 Saturday half- holidays in the air-chamber, thereby finding relief 

 from their pain. Acting on the idea suggested by this fact, Mr. 

 Moir, the engineer in charge of the Hudson River Tunnel, has had 

 constructed a compressed-air hospital for the men employed in 

 the tunnel, among whom there have been several severe cases of 

 " bends," although the air-pressure is not particularly high; never, 

 indeed, exceeding thirty pounds per square inch. The hospital, 

 as described in Engineering, is a cylinder 18 feet long by 6 feet in 

 diameter, constructed of steel plates three-eighths of an inch and 

 half an inch thick, and divided into two chambers by a transverse 

 bulkhead. One of these chambers acts as an air-lock for the 

 other, and both are fitted up with beds and every thing necessary 

 for the comfort of the patients. The air-pressure is maintained 

 by a pump, a constant supply of fi-esh air being secured by keep- 

 ing a pet-cock in the shell of the hospital open, through which 

 the air continually leaks out. A safety-valve is also suppMed to 

 prevent over-pressure, should the pumps run away. 



— A long article by Dr. von Danckelman, containing details 

 concerning the atmospheric phenomena of the Guinea coast, is 

 thus summed up in The Scottish Geographical Magazine tor J a\j: 

 " These depend in the main on the atmospheric pressure over the 

 lands of North A.frica, and especially the Sahara, where the mean 

 temperature in summer rises above 98° F. The low pressure thus 

 produced draws in the air from all sides to restore equilibrium. 

 Hence the prevalent winds on the Guinea coast during this season 

 are the south and south-west; while in winter the contrary phe- 

 nomenon occurs, except sometimes on the shore, where the higher 

 temperature of the land maintains a continuance of southerly 

 breezes. The highest pressure occurs in July and August, and 

 the lowest in February and March. The range of the monthly 

 mean is small, amounting only to from .14 to .18 of an inch. As 

 regards temperature, it is found that the maximum occurs in 

 February and April, and the minimum in July or August. The 

 mean daily range is nearly twice as great in the hottest season as 

 in the coldest, and increases considerably towards the interior. 

 In Bismarckburg the mean maximum (in March) was 87.7° F., 

 and thf) minimum (in July and August) 65.3°, and the maximum 

 and minimum ranges 23.6° and 13.8° respectively. At Akassa the 

 average daily range is only 10°, while at Bismarckburg it is 18.5°. 

 Turning now to the rainfall, it appears that a rainy season of four 

 months sets in shortly before the sun reaches the zenith, which it 

 does in the beginning of April, and that the maximum fall occurs 

 in May and June. About the latter part of June, the dry season 

 commences, and lasts till the middle, and sometimes the end, of 

 September. The yearly rainfall at Bismarckburg is over 59 inches; 

 at Accra, 29; at Christiansborg, 22.6. Half the storms come from 

 directions lying between north-east and south-east, most of them 

 from the north-east. Tornadoes are most frequent before the 

 commencement of the rainy season. The most singular phenome- 

 non on this coast is the Harmattan, a dry wind, laden with dust, 

 and often bringing with it hazy and cloudy weather. On the 

 Senegal it follows an east to east-south-easterly direction; on the 

 Gold Coast and near the mouth of the Niger, a more northerly 

 course; and it blows most frequently in December and February." 



