October 1, 1897.] 



KNOWLEDGE. 



241 



weight of ancient silver bijouterie, some of which is 

 evidently of ancient Arabic workmanship. It would seem 

 a pity that the English coins of Canute and Ethelred 

 should go to the numismatic collection in the Ermitage at 

 St. Petersburg, instead of to the British Museum. 



COMING COLD. 



By Alex. B. MacDowall, M.A. 



TO a practical mind the small amount of insight 

 hitherto gained into coming weather, may well 

 appear a somewhat meagre result of the immense 

 industry that has been expended in observation 

 and study of the weather. We receive, with mild 

 thankfulness, the small mercy of a daily weather forecast 

 that comes with our morning paper. 

 But there is probably no competent °- 

 meteorologist in this country who will 

 undertake to say what weather we 

 shall have next week, or month, or 

 winter, or year. If anyone were to 

 apply at head-quarters in Westminster 

 for enlightenment on such points, he 

 might come away, I suspect, thinking 

 of that line in the " Biglow Papers": — 



" Never say nuthin' that you can be 

 held to." 



We are offered, indeed, from time 

 to time, a complete daily weather 

 programme for a whole year. Some- 

 how, we do not find ourselves very 

 eager to shape our conduct by these 

 remarkable instructions. 



The science of meteorology is still 

 in its youth, and we may with reason 

 hope for considerable advance in 

 future beyond the point now reached. 

 If we ever attain to a method of long 

 weather forecasts, we may be sure it 

 will only bo after many attempts, and 

 many failures ; just as will be the 

 case if we ever reach the North Pole 

 or learn to fly. By all means (we 

 should say) let such attempts be 

 made. And if we must occasionally 

 smile when some ardent meteorolo- 

 gist " comes a cropper," let us re- 

 member, and hope, that he may do 

 better next time ! 



Taking a wide survey, there are not wanting signs that 

 progress is being made. Some instances may here be 

 given. 



The able officials of the Indian Meteorological Service 

 now find themselves in a position to issue, early in June, 

 a useful forecast of the summer or south-west monsoon ; 

 being guided by a consideration of various factors — the 

 strength of the south-east trades, the snowfall in the 

 previous winter, etc. Details of this interesting achieve- 

 ment will be found in Nature of 26th November, 1896. 



From a recent paper contributed to the MeteoroJixjische 

 Xeitschrift it would appear that in Hungary Herr Eriesenhof 

 has attained considerable success in forecasting the 

 weather of that country about a fortnight in advance. 

 He finds that on certain days, determined chiefly by 

 positions of the moon, the barometric configuration over 

 Europe is peculiarly liable to change. 



The weather in India is of course much moi-e regular 



than ours. And Hungary is rather off the course of those 

 numerous depressions by which the weather of Western 

 Europe is largely determined. 



Dr. Maurer, of Zurich, has still more recently {Meteoro- 

 lof/ische Zeitschrift, July, 1897) shown reason for expecting 

 that about the beginning of next century we shall be 

 entering upon one of those warm periods whose centres, 

 according to Bruecknev, recur at about thirty-five years' 

 intervals (cold periods intervening ) ; so that we may then 

 (in Western Europe) look for a series of warm and very 

 warm summers, with, occasionally, very mild winters. 



It is obviously in past experience that we must search 

 for a clue to the character of weather that is to come, and 

 I propose now to ask whether the records of winter cold, 

 at Greenwich, throw any light on coming cold. We may 

 roughly measure cold by the number of frost days, and 



'() '62 



S tfttr 'i,. 



we shall confine our attention to the number of those in 

 the first quarter of the year. (We might have taken the 

 total number in the year, or some other portion, with 

 similar, though perhaps leas definite, results.) 



About the middle of the diagram herewith will be seen 

 a number of dots joined by dotted lines (/)). This is the 

 curve of variation of the number of frost days in the first 

 quarter since 1841. In the smoothed thick line curve 

 traversing it ('/) each year point represents an average 

 of fire of the values dealt with. 



Above these curves is a curve of sunspots inverted (that 

 is, the low points represent many spots, the high 

 points few spots) ; and when we compare it with the 

 smoothed curve of frost days, we find considerable corre- 

 spondence, the crests of the latter coming near (sometimes 

 rather before) minima of sunspots, and the hollows near 

 (sometimes rather after) maxima of eunspots. 



If, in a similar way, we draw a curve of the number of 



