October 31, 1901] 



NA TURE 



665 



procure and maintain fine breeds of cattle and so forth, which 

 are costly, but repay in satisfaction. 



There is yet another existing form of princely benevolence which 

 might be so extended as to exercise a large effect on race improve- 

 ment. I mean the provision to exceptionally promising young 

 couples of healthy and convenient houses at low rentals. A 

 continually renewed settlement of this kind can be easily 

 imagined, free from the taint of patronage, and analogous to 

 colleges with their self-elected fellowships and rooms for resi- 

 dence, that should become an exceedingly desirable residence for a 

 specified time. It would be so in the same way that a good club 

 by its own social advantages attracts desirable candidates. The 

 tone of the place would be higher than elsewhere, on account of 

 the high quality of the inmates, and it would be distinguished 

 by an air of energy, intelligence, health and self-respect and by 

 mutual helpfulness. 



Prospeits. — It is pleasant to contrive Utopias, and I have 

 indulged in many, of which a great society is one, publishing 

 intelligence and memoirs, holding yearly elections, administer- 

 ing large funds, establishing personal relations like a missionary 

 society with its missionaries, keeping elaborate registers and 

 discussing them statistically with honest precision. But the 

 first and pressing point is to thoroughly justify any crusade at all 

 in favour of race improvement. More is wanted in the way of 

 unbiased scientific inquiry along the many roads I have hurried 

 over, to make every stepping-stone safe and secure, and to make 

 it certain that the game is really worth the candle. All I dare 

 hope to effect by this lecture is to prove that in seeking for the 

 improvement of the race we aim at what is apparently possible 

 to accomplish, and that we are justified in following every path 

 in a resolute and hopeful spirit that seems to lead towards that 

 end. The magnitude of the inquiry is enormous, but its object is 

 one of the highest man can accomplish. The faculties of future 

 generations will necessarily be distributed according to laws of 

 heredity, whose statistical effects are no longer vague, for they 

 are measured and expressed in formulae. We cannot doubt the 

 existence of a great power ready to hand and capable of being 

 directed with vast benefit as soon as we shall have learnt to 

 understand and to apply it. To no nation is a high human 

 breed more necessary than to our own, for we plant our stock all 

 over the world and lay the foundation of the dispositions and 

 capacities of future millions of the human race. 



OCEAN CIRCULATIONS 



'T'HE investigation carried on by Mr. H. N. Dickson into the 

 distribution of temperature and salinity in the surface water 

 of the North Atlantic is one of great importance. It promises, 

 if continued, to be of considerable value, not only to those who 

 are especially interested in studying the circulation of the surface 

 water of the Ocean, but also to meteorologists generally and 

 particularly to those who see, in a comparison of the varying 

 yearly temperatures of the North Atlantic with that of a mean 

 for the season, the key to a clearer knowledge of the causes 

 which combine to influence the climate of western Europe, and 

 especially of our Islands, and who look hopefully in that 

 direction for information whereby future modifications in the 

 conditions of climate may be foretold for periods some time in 

 advance. 



The treatise before us, setting forth the author's method of 

 conducting the research and the results at which he arrived, was 

 contributed to the Royal Society in March, 1900. 



In introducing his subject the author says: " The history of our 

 knowledge of the currents of the North Atlantic Ocean up to 

 the year 1S70 has been written once for all by Petermann," 

 whom he quotes at some length, remarking " that the con- 

 clusions, then arrived at, were not modified by the observations of 

 the next twenty years." 



During the years 1S96 and 1897 materials were collected for 

 preparing the charts of temperature and salinity, the parallel of 

 40" N. being selected as the southern boundary of the area for 

 investigation. The observations of temperature were furnished 

 by the Meteorological Office, the Danish Meteorological Depart- 

 ment, the United States Hydrographical Department, and the 

 Bureau Central Meteorologique de France, and by Prof. 

 Pettersson. The samples of water for the determination of 

 salinity were obtained from the captains of vessels keeping logs 



1 Phil. Trans, of the Royal Society :— " The Circulation of the Surface 

 Waters of the North Atlantic Ocean." By H. N. Dickson. 



NO. 1670, VOL. 64] 



for the Meteorological Office and for the Danish Hydro- 

 graphical Department, specially made bottles being supplied to 

 them for the purpose, and no care being spared in guarding 

 against impurity or the introduction of any matter that could 

 give rise to error in the analytical determinations. 



The accuracy of the method adopted in estimating the salinity 

 of the samples was subjected to severe scrutiny. The author 

 states the results of his observations, demonstrating the distribu- 

 tion of temperature and salinity for each month during the year 

 1S96 as shown in the charts prepared by him, in which the 

 isotherms and isohalines are supplemented by a scale of colour- 

 ing denoting areas having the same range of temperature and 

 the same range of salinity. He calls attention to the general 

 agreement between the distribution of salinity as shown on the 

 one set of charts and that of temperature as shown on the other 

 set when apparent, and notes departures and irregularities when 

 they occur. He then deals in the same manner with the 

 observations of 1S97 and compares results. 



Taking the means of each month respectively for the two 

 years, the distribution of temperature, as shown on these charts, 

 corresponds fairly well with the distribution of sea-surface 

 temperature given on the quarterly sea-temperature charts on 

 the North Atlantic, issued by the Meteorological Office in 18S4. 



For the purpose of defining the limits of ocean currents and 

 of arriving at some estimate as to its relative velocity in different 

 localities, the information to be gained by the thermometer is 

 invaluable, for over areas little frequented by shipping where 

 current observations are necessarily sparse, a comparatively 

 insignificant number of sea-surface observations will suffice to 

 indicate the existence or failure of an ocean stream ; and if to 

 these detective signs be added observations of salinity, the 

 evidence acquired becomes still more complete. 



The effects of the cold water from the north in deflecting the 

 warm stream from the westward are clearly shown on these 

 charts, which, when seasonal variation in temperature has been 

 made allowance for, appear in good agreement (speaking 

 generally) with the monthly current charts of the North Atlantic, 

 published by the Admiralty, as regards the area over which the 

 warm water of the Gulf Stream is distributed each month, and 

 the northern and western limits to which it reaches. The indi- 

 cations of the existence of Gulf Stream water, stated roughly, 

 may be traced on the Admiralty Chart to the following limits in 

 the given months : — 



January. — The stream does not reach to the eastward oi 

 20° W. , and a south-easterly set is apparent off Ireland. 



February. — In 55° N. it reaches 15' W. ; a south-easterly set 

 is found to the westward of Ireland, and a south-westerly to the 

 south-westward of the Fastnet Rock. 



March. — It has advanced to the coast of Ireland. 



April. — In 55° N. its limit has receded to 20° W., and the 

 Iceland south-going current begins to show itself north of 

 55° N. 



May. — The Gulf Stream and Davies Strait cold current com- 

 mingle in 47° N. 27° \V., the Iceland current sets S. and S. W. 

 to 48" N. 30= W. 



June. — Gulf Stream to 15° W. in 52° N. Iceland and 

 Denmark Strait cold currents to Irish coast. 



July. — To the S. of 50" N. it joins the Iceland and Denmark 

 Strait current in about 48' N. off the Bay of Biscay. 



Augusl. — It extends to the north of Ireland but is modified 

 in about 20' W. bv a south-going set. 



September. — It extends to the north of Scotland. 



October. — It is found in 10° W. in 59° N. 



November. — The data are insufficient, but the Stream is trace- 

 able to 19" W. in 59' N. 



December. — It is difficult to trace the Stream eastward of 

 40" N. in 45' W. A south-going cold current is shown to the 

 north-westward and westward of IreUand ; there is a persistent 

 southerly (S. E. to S.W. ) movement of water in the eastern half 

 of the Atlantic. 



Mr. Dickson's charts show the existence of Gulf Stream water 

 to the northward and westward of the limits given above for 

 several months, notably on the January chart, and the explana- 

 tion doubtless is that the value of the current being small, it has 

 been inappreciable in navigation. 



There exists, during the greater part of the year, a movement 

 of water eastward, which divides, at a varying distance to the 

 westward of the English Channel. One arm branches towards 

 the Bay of Biscay, the other northward (Rennell's Current). 

 The latter is well known to the captains of the large 



