556 



NATURE 



[^April 26, 1877 



however, any readily apparent argument against the 

 theory that it has been all dry land and at one and the 

 same time. Let us for a while assume that it was, and 

 let us then see what facts about climate we may infer 

 with regard to it. 



There are no doubt many other places besides those 

 already known where the depth exceeds 3,000 fathoms. 

 Let us, however, take the group of the known three which 

 run in a line north-east and south-west, and are respec- 

 tively 3,450, 3,200, 3,250, and we may assume that they 

 represent a valley line. Let us suppose that the area is 

 raised till this valley is dry land ; what then will be the 

 height of our ridge, and what will be the highest peaks 

 of the country ? To the north-west of the valley, distant 

 about as far as from here to the Grampians, would tower 

 the peaks, now the islands of St. Paul's Rocks, and 

 Fernando de Noronlia, rising some 30,000 feet ; and 

 to the south-east would rise Ascension to a similar 

 height. The "ridge" itself v/ould be about 15,000 feet. 

 There is no reason whatever for supposing that the 

 ridge is a table land. On the contrary, it seems more pro- 

 bable, judging from the variations in the soundings, that 

 it was diversified with hills and valleys. Now a ridge of 

 this elevation would, in all probability, have a snow cap- 

 ping even at the equator. Astronomers tell us that in 

 "former" times the earth's atmosphere was higher and. 

 its pressure greater than now, but that was in a very 

 remote past, and we may fairly assume that at the time 

 of this ridge being land the atmospheric conditions were 

 much as now. We should thus have a mountain ridge 

 with hot valleys and every variation in temperature 

 according to height ; so that so far as temperature is con- 

 cerned botanists would have no difficulty in accounting 

 for the migration across the equator of plants that would 

 be killed by great heat. With regard to the part of the 

 ridge between Europe and America, answering to Unger's 

 "Atlantis," the soundings are more numerous. The 

 undulations seem to have been many, and the general 

 elevation was probably not more than 9,000 feet, unless 

 the original depths are masked considerably by a deposit 

 of globigerina-ooze. Some peaks — now the Azores — still 

 remain above water. When the ridge sank is a ques- 

 tion on which we have at present no evidence. The 

 whole subject is still young, and we have much yet to 

 learn. 



In conclusion the lecturer said : I hope I have given 

 sufficient prominence to the distinction that must be 

 drawn between fact and inferences from those facts. 



I should be very sorry for anyone to go away from this 

 place and say that they heard a lecture at South Ken- 

 sington in which they were told that there formerly was a 

 continent nmning down the middle of the Atlantic, and 

 that there was a lofty mountain ridge along it, capped 

 with snow even at the equator, 



I wish carefully to point out to you I have made no 

 statement of the kind. I have simply told you the fact 

 that a ridge less than i.ooo fathoms beneath the ocean 

 runs down mid Atlantic in a sinuous course, whose 

 contour is roughly indicated by the diagram. That on each 

 side of it are ocean depths, twice and in some cases thrice 

 the distance it is below the sea-level. That if these 

 depths were once land valleys, as geologists have no diffi- 

 culty in believing possible, then there would be a ridge 

 running north and south along the area of what is now 

 the deep Atlantic, ranging from 9,000 to 15,000 feet above 

 the sea-level, and that if the atmospheric conditions were 

 the same then as now, judging from what we know of the 

 Andes under the equator at the present time, there was 

 protably a snow- capping. 



Such a land-connection between Europe and America, 

 if it existed as late as Tertiary times, would meet the re- 

 quirements of Unger's hypothesis, varying in height as it 

 sank, and the whole ridge would afford a solution of any 

 difficulty botanists may have on the score of temperature 



in accounting for the migration of cold-loving and heat- 

 shunning plants across the torrid zone. 



The remarks at the conclusion of the lecture, in refer- 

 ence to its being the last of the series, we have already 

 reported at p. 490. 



REMARKS ON THE INVESTIGATION OF 

 CUM A TES 



'T^O Prof. Balfour Stewart we are indebted for the 

 -^ separation of meteorology into its two great divi- 

 sions of physical and climatic. The latter I have pro- 

 posed to separate into two sub-divisions, viz., normal and 

 abnormal. The first of these subordinate branches in- 

 cludes the investigation of the usual states of the atmo- 

 sphere in different parts of the earth's surface, as ascer- 

 tained by periodic data derived from the averages of 

 observations continued for a series of years. The second 

 subordinate branch has for its object the investigation of 

 unusual temporary disturbances of the equilibrium of the 

 atmosphere — such, for example, as storms of wind, by 

 means of the comparison of individual observations, 

 extending over only a few hours or a few days. 



We need hardly wonder at the disfavour with which 

 meteorology is regarded by some men of the highest 

 standing in physical science, from whom valuable assist- 

 ance might have been expected ; for we know that there 

 is a great want of agreement among meteorologists them- 

 selves as to the means of determinmg even the most im- 

 portant fundamental data. For example, it will hardly, 

 one would think, be disputed that the essential condition 

 in all meteorological inquiries is iiniformity in instru- 

 mental obsei'iiation. But towards the establishment of a 

 uniform international system no progress has as yet been 

 made. Points of subordinate importance may have been 

 adjusted at the Congress meetings at Leipzic and Vienna, 

 but this all-important question remains just where it 

 was. To Mr. Glaisher is due the adoption among his 

 observers of the uniform height of 4 feet above the 

 ground for thermometers, and one invariable form of 

 screen for protecting them. The Scottish Meteorological 

 Society, when establishing their stations in 1855, followed 

 the example of Mr. Glaisher by adopting the 4-feet 

 standard height, and they ultimately selected the form of 

 double-louvre boarded protecting box, which I proposed 

 in 1864. The Meteorological Society of England have 

 also adopted the same uniform system as that in Scotland 

 of boxes, and their exposure, and hours of observation. 

 But other observers follow different methods, and on the 

 Continent it is believed there is still less approximation 

 to uniformity than among ourselves. The very first 

 matter which should be taken up by home and foreign 

 meteorologists is the settlement once for all of the ques- 

 tions how, when, and with what position and exposure of 

 instruments are observations to be made. Until this is 

 done it is impossible to arrive at useful results, because 

 the observations which are now being obtained at different 

 stations are not comparable the one with the other. Un- 

 less there be some such general Council as that lately 

 proposed in Nature by Prof. Balfour Stewart for carry- 

 ing out this and other important objects, 1 shall certainly 

 despair of the future of this new science. 



But let us now see in what way the mode o| 

 instrumental observation bears on the subject of cli- 

 mate. Climates may be defined as states of the atmo- 

 sphere due to the joint operation of geographical, geo-* 

 logical, and other conditions more or less local, and they 

 are judged of by their effects on animal and vegetable 

 lile. Ihey do not, therefore, depend simply on the geo- 

 graphical position on the earth's surface of the district 

 where the observations are made, but are largely affected 

 by varicus conditions, such as the distribution of land 

 and water, the nature of the soil and its covering, and the 

 elevation or depression and character of the land at, and 



