3°4 



NA TURE 



\Jan. 29, 18S0 



severe design alone will suit tha locality, which we will 

 presently describe, and may safely be left to the discretion 

 of a committee of taste by a general meeting of the sub- 

 scribers to the memorial as only a small sum of money 

 need be expended on this object ; but |\ve would ask it 

 this alone will appease the manes of Edmund Halley ? 

 We must give further explanations. 



Within sight of Halley's Mount are tiuo disestablished 

 observatories. One, the most important, is that on Ladder 

 Hill, with this inscription over the doorway : " h.ec 

 SPECULA ASTRONOMICA Condita fuit AD. MDCCCVII." 

 This was Johnson's observatory, broken up when the 

 Imperial Government took the island from the East India 

 Company in 1834. It is now used as a mess-room for 

 the officers, R.A. and R.E., at Ladder Hill. 1 The other 

 is at Longwood, and was established in 1840 by Sabine 

 as a magnetic and meteorological observatory; this 

 station was broken up in 1845. In front of it on Dead- 

 wood Plain is the base-line measured by Lefroy, 2,9863 

 yards in length. 



The re-establishment of these valuable observing stations 

 would indeed be a lasting memorial such as Halley would 

 approve. Of the fitness of the first-named station as an 

 astronomical observatory, we need only judge from the 

 actual work accomplished there by Johnson and by Gill's 

 appreciation of its position and capabilities. Of the 

 second it will be manifest to all meteorologibts, what an 

 advantage such an establishment in the heart of the 

 south-east trades would be to science; whilst Halley's 

 magnetical researches could be renewed in an island 

 where the atmospherical electricity is so seldom disturbed 

 that lightning conductors are never fitted to the powder 

 magazines, and where distant thunder is heard seldom 

 more than once in a generation. 2 



A few more words may not be out of place to describe 

 Halley's Mount. Nearly in the centre of the island it 

 commands from its elevation of 2,400 feet, the whole of 

 the northern portion of St. Helena. Four miles looking 

 due north is the northern extremity of the island called 

 Sugar-loaf, and four miles to the right is Dry-gut Bay and 

 Stone-top, whilst the same distance to the left or west, is 

 Bennett's Point. Throughout the whole of this northern 

 semicircle, the view is bounded only by the sea horizon. 

 Behind us the crateral ridge just under 3,000 feet hides 

 the southern coast, which is d stant only three miles in 

 Sandy Bay. But although this ridge hides the view, it 

 forms a fine background and shelter against the southern 

 winds. Above Halley's Mount the mountain-tops arc 

 covered with indigenous vegetation, shrubby Campanu- 

 laceae, Scajvolese, mosses, lycopods, and arborescent 

 Dicksonias, and the peculiar composite trees with cauli- 

 flower-like blossoms, much the same as when Halley was 

 here two centuries ago ; but beneath us, how changed. 

 As Sir Joseph Hooker observed in a lecture on " Insular 

 Floras," at the Nottingham meeting of the British 

 Association in 1866, in reference to St. Helena : — " When 

 discovered about 360 years ago, it was entirely covered 

 with forests, the trees drooping over the tremendous 

 precipices that overhang the sea. Now all is changed, 

 fully five-sixths of the island are utterly barren, and by 

 far the greater part of the vegetation which exists, whether 

 herbs, shrubs, or trees, consists of introduced European, 

 American, African, and Australian plants." On Halley's 

 Mount the indigenous and exotic plants meet on equal 

 terms, a fit vegetation to surround a cosmopolitan relic. 



the south Crux. On the east the inferior planets, and on the west the comet. 

 On the twelve seats are the signs of the Z diac (has any one remarked that 

 the conventional signs of the Zodiac have become a recognised ornamental 

 pattern on the jewellery made by the natives on the west coast of Africa ?) and 

 the names of astronomical workers in the southern hemisphere 



* See "Six Months at Ascension," p. 26. David Gill's feelings at viewing 

 this degraded observatory, remind us of H alley's disappointment on reaching 

 Greenwich, on his appointment as King's Astronomer, 1720, and finding that 

 the executors of Flamsteed had removed all the instruments See Whewcll s 

 "Inductive Science," vol. ii. Compare also the desolation of Uraniburg. 



~ We have not been able to ascertain in which observatory Capt. Foster's 

 pendulum experiments were carried on between 1828-1831,^1 we presume 

 n Johnson's observatory; nor are we sure where Maskelyne's station was. 



In the present day the most conspicuous features in the 

 landscape of St. Helena, as viewed from the highlands, 

 are the sombre plantations of pinaster (only introduced in 

 1 7 87), which contrast strongly with the willow-leaved 

 acacias of New South Wales ; whilst on all sides are ever 

 wider extending acres of Fhormium tenax, grown for the 

 sake of its economical fibre, and whose seeds afford 

 capital fare to the numerous Chinese pheasants which 

 inhabit the covers on the sides of Halley's Mount. 



THE U.S. WEATHER MAPS 



WE are again enabled, through the courtesy of Gen. 

 Myer, of Washington, to present our readers with 

 two Weather Maps of the War Department of the United 

 States, which graphically present the mean pressure and 

 temperature for the whole of the Northern Hemisphere of 

 the earth tor April, 1878, and the tracks of the centres of 

 storms for the same month. As these maps are con- 

 structed from the observations of all the stations reporting 

 to the Army Signal Service, they must be held as very 

 accurately representing the meteorology of the period, 

 and they may serve to show the extraordinary energy 

 with which this well-directed meteorological system is 

 conducted and turned to account in the interests of the 

 public and of science. 



The outstanding characteristic of the weather of 1878 

 was its extraordinarily high temperature to the east of the 

 Rod,y Mountains, chiefly in the upper valleys of the 

 Missouri and Mississippi, and the Lakes region, rising in. 

 the latter to nearly 1 i°'o above the mean of the month. 

 April is one of the months in which the western prairies 

 receive their annual maximum of rain, but during April, 

 1878, this maximum rose greatly above its normal amount, 

 the rainfall of the basins of the Mississippi and its 

 affluents, with the exception of Ohio, being generously 

 large. In Minnesota the fall was nearly four inches in 

 excess of the average. The region of absolutely heaviest 

 rainfall covered a broad track extending from St. Louis, 

 Mo., to Florida. 



These characteristics of the distribution of the tem- 

 perature and rainfall were impressively felt in the singular 

 distribution of atmospheric pressure, which everywhere 

 was under the average of April, but most pronouncedly so 

 to the west and north-west of the regions of the extreme 

 excess of temperature and rainfall. The deficiency at 

 Omaha amounted to fully two-tenths of an inch, an. 

 unusual deficiency for that region and season. 



Turning now to the map of the tracks of the centres of 

 the storms of April, 1878, we observe that most of them 

 group together and lingered longest in this very region of 

 low pressure, and that immediately to the cast and south- 

 east lay those regions where temperatures ranged so 

 unusually high, rain tell so copiously, and thunderstorms 

 played so strikingly brilliant a role among the weather 

 phenomena of the month. 



These tracks of the different storm centres admirably 

 illustrate some of the more prominent types of the States 

 storms. Storm No. I. is seen to branch into two shortly 

 alter it began its advance on the States, the one passing 

 northwards and dying out after one day's course, near the 

 Cumberland River, whilst the other pursued a north- 

 easterly course toward Newfoundland. No. II. originated 

 to the east of Pike's Peak, and after a two days' course 

 to north-north-east, was lost sight of in Canada for want 

 of the observations necessary to trace its course over that 

 part of the Dominion. Whilst this storm had its centre 

 over Minnesota, a deep barometric trough ran southward 

 into the Gulf of Mexico— a feature of American storms of 

 no unfrequent occurrence— and the ram area extended 

 eastward over the lakes, the middle, and South Atlantic 

 States, with frequent heavy thunderstorms, accompanied 

 with hail. Storms IV. and V. illustrate the coalescence 



