March 31, 1887] 



NA TURE 



517 



The density (at i5'''56 C.) of the sea-water which comes 

 in contact with the lower surfaces of the icebergs is 10255, 

 which represents a chlorine percentage of rgo. Ice 

 actually iiieltiiii; in this water would produce a temperature 

 of - r'92 C. When ice is imiih-rscd\x\ this water it lowers 

 its temperature, and a portion of the ice is melted, produc- 

 ing dilution. The concentration, therefore, or chlorine 

 percentage, which will determine the melting temperature 

 of the ice, will be a little lower than that of the original 

 sea-water. From the Challciii^cr observations we see 

 that, on the confines of the pack-ice the cold stratum of 

 water has a uniform temperature of 29' F. ( - i 67 C). Ice 

 melts at this temperature in sea-water containing r65 per 

 cent, of chlorine. In this process ice is melted, so that 

 100 grammes pure warm sea-water become 1 19 grammes 

 of diluted cold sea-water. It will be observed that the ice 

 which has been formed in the atmosphere at a tempera- 

 ture of 32° F. comes in this way to be melted at a tem- 

 perature of 29° F. ; and the pressure exerted by the 300 

 fathoms of sea-water, though it may assist in the lowering 

 of the melting temperature, is insufficient to account for 

 the amount. 



TO FIND THE DA Y OF THE WEEK FOR ANY 



GIVEN DA TE 

 TT AVI NG hit upon the following method of mentally 

 *■ *^ computing the day of the week for any given date, 

 I send it you in the hope that it may interest some of 

 your readers. 1 am not a rapid computer myself, and 

 as I find my average time for doing any such question is 

 about 20 seconds, I have little doubt that a rapid computer 

 would not need 15. 



Take the given date in 4 portions, viz. the number of 

 centuries, the number of years over, the month, the day 

 of the month. 



Compute the following 4 items, adding each, when 

 found, to the total of the previous items. When an item 

 or total e.xceeds 7, divide by 7, and keep the remainder 

 only. 



i'hc Century-Ilcm. — For Old Style (which ended 

 September 2, 1752) subtract from 18. For New Style 

 (which began September 14) divide by 4, take overplus 

 from 3, multiply remainder by 2. 



The Ycar-Ilcm. — Add together the number of dozens, 

 the overplus, and the number of 4's in the overplus. 



The Month-Iton. — If it begins or ends with a vowel, 

 subtract the number, denoting its place in the year, from 

 10. This, plus its number of days, gives the item for the 

 following month. The item for January is "o"; for 

 February or March (the 3rd month), " 3 " ; for December 

 (the 1 2th month), " 12." 



The Day-Item is the day of the month. 



The total, thus reached, must be corrected, by deduct- 

 ing " I '■ (first adding 7, if the total be "o"), if the date 

 be January or February in a Leap Year : remembering 

 that every year, divisible by 4, is a Leap Year, excepting 

 only the century-years, in New Style, when the number 

 of centuries is tioi so divisible {e.i^. 1800). 



The final result gives the d^y of the week, " o " mean- 

 ing Sunday, " i " Monday, and so on. 



Examples 

 1783, September 18 



17, divided by 4, leaves " i " over ; i from 3 gives " 2 " ; 

 twice 2 is " 4." 



S3 is 6 dozen and 11, giving 17 ; plus 2 gives 19, i.e. 

 (dividing by 7) " 5." Total 9, i.e. " 2." 



The item for August is "8 from \o"'i.e. "2" ; so, for 

 September, it is "2 plus 3,'' ;>. "5." Total 7, ;>. " o," 

 which goes out. 



iS gives "4." Answer, " Thursday'' 



1676, February 23 



16 from 18 gives " 2." 



76 is 6 dozen and 4, giving 10 ; plus i gives i \,i.e. " 4." 

 Total " 6." 



The item for February is " 3." Total 9, i.e. " 2." 



23 gives "2." Total "4." 



Correction for Leap Year gives " 3." Answer, 

 " li'ed/iesday." Lewls Carroll 



NOTES 

 In the Report submitted yesterday at Edinburgh to the half- 

 yearly general meeting of the Scottish Meteorological Society, 

 the Council state that the work at the Ben Nevis Observatory 

 continues to be carried on by Mr. Omond and the assistants in 

 the same highly satisfactory manner as has been recorded in 

 previous Reports. In addition to the laborious work of observ- 

 ing at all hours of the day and night, of reducing the observa- 

 tions, and forwarding copies for the Society and the Meteoro- 

 logical Council, the staff of the Observatory has given very 

 effective assistance in the preparation of the tables of the 

 meteorology of Ben Nevis now in the press. Several interesting 

 researches are being conducted at the Observatory, the result.s 

 of which will be communicated to a future meeting. The 

 Directors took steps last autumn to raise subscriptions to clear 

 off the debt on the institution, and to establish a low-level 

 station at Fort William, at which hourly observations may 

 be made for comparison with those at the Observatory. It 

 is only by two sets of observations at the top and bottom 

 of the mountain that the Ben Nevis Observatory can be utilised, 

 with the de>ired success, in the furtherance of meteorological 

 science, but particularly in that branch of it which concerns the 

 improvement of the system of forecasting the weather of the 

 British Islands. 



On Tuesday evening last the Lord Advocate stated in the 

 House of Commons that the Scottish Universities Bill would 

 shortly be introduced. 



The Paris Medical Faculty has decided to .alter considerably 

 the mode of competition for its Fellowships. The general object 

 of the changes is to secure more original workers. The thesis 

 (which has usually been the work, not of the candidate himself, 

 but of his friends) is to be suppressed. Each candidate will 

 henceforth have to deliver a lecture on his own scientific 

 researches. 



The French Chamber of Deputies has decided that the build- 

 ings of the College of France shall be considerably enlarged. 

 Fifty years ago, when this institution had only seventeen pro- 

 fessors, its present buildings were sufficient ; but now, when it 

 has forty-one professors, they are very inadequate. It is to 

 have four new lecture-rooms, a geological gallery, a set of rooms 

 for other collections, a library, a meeting-room for professors, 

 and eight laboratories. These additions will cost over 9,000,000 

 francs. 



The Anatomical Society, founded last September at Berlin, 

 will hold its first general meeting at Leipzig on April 14. The 

 Society has now over 170 members in England, Germany, 

 Austria, Hungary, Switzerland, Holland, Belgium, Scandinavia, 

 France, Russia, Italy, and North America. 



Dr. Hans Reuch, who has lately devoted much time to the 

 study of earthquakes in Norway, has issued a tabulated circular, 

 which has been reproduced in the entire Norwegian Press, 

 requesting that reports of any phenomena observed in con- 

 nexion with earthquakes may be sent to him. By Government 

 permission all such reports may be transmitted through the 

 post free of charge. Dr. Reuch asks especially for information 



