July 29, 1920] 



NATURE 



691 



Our Astronomical Column. 



The Date of Easter. — It seems a curious 

 anachronism that our calendar in the twentieth 

 century should still be largely influenced by the 

 lunar chronology which passed out of direct use 

 nearly two thousand years ago. That was the most 

 obvious system to employ at the dawn of astronomy, 

 the moon's rapid motion and the ease of locating its 

 position in the heavens making it far superior to the 

 sun as a time-measurer. But as time went on the 

 inconvenience of having a variable number of months 

 in the year, and of having events like the equinoxes 

 and solstices occurring on variable dates, caused the 

 system to be abandoned and a purely solar calendar 

 substituted. 



The Passover was, of course, on a fixed date of the 

 lunar calendar, the fourteenth day of the first month, 

 and, owing to the close association of this feast with 

 the events commemorated at Easter, an attempt has 

 been made to follow the ancient system of fixing its 

 date. That this is mainly the result of sentiment is 

 shown by the fact that Christmas and other feasts 

 are kept on fixed days of the solar year; moreover, 

 the coincidence with the ancient method is not per- 

 fect, since Easter is tied to one day of the week, 

 which was not the case with the Passover. This 

 fact alone may produce a deviation of six days, so 

 that it is obvious that no serious principle could be 

 involved in increasing the deviation to a fortnight or 

 thereabouts, which is all that a fixed date demands. 

 Many unofficial ecclesiastical pronouncements have 

 shown that there is no strong hostility to such a 

 change. Lord Desborough brought the matter 

 forward in a letter to the Times on July 20, 

 and in the House of Lords on the following 

 day, pointing out the inconvenience felt by the 

 schools, universities, law terms, etc., through the 

 variable date. The Earl of Onslow did not give 

 much hope of Government action, but this is clearly 

 a matter for international, not merely national, ar- 

 rangement. The Astronomical Union in its session 

 at Brussels last July appointed a Committee on 

 Calendar Reform, with Cardinal Mercier as chair- 

 man, and it is understood that the date of Easter 

 was one of the subjects of reference. The present 

 time, when so much is in the melting-pot, would 

 seem to be a particularly hopyeful one for promoting 

 this and similar reforms. 



Astronomy in Town Planning. — It is a sign of 

 awakening public interest in astronomy that a paper 

 should be read before the Ottawa centre of the 

 R.A.S. of Canada on the importance of considering 

 practical questions of incidence of sunlight in planning 

 out new towns. The author, Mr. H. L. Seymour, 

 refers to the action of sunlight on bacteria and to the 

 impwrtance of letting all rooms get their share of 

 sunlight, which is best secured by making the corners 

 of the houses point to the four cardinal points, which 

 means that the streets should run from N.E. to 

 S.W. and from N.W. to S.E. He quotes Mr. Horace 

 Bushnell as having put forward the same idea in 

 1864; but, nevertheless, the tendency has been rather 

 to make the streets run N.-S, and E.-W., with the 

 result that northward walls get no sunshine at all 

 for more than half the year. In the planning of 

 garden cities, where the houses are not contiguous, 

 it is also important to place them so that the shadow 

 of one house may not fall on another, or at least to 

 minimise such incidence. The heights of buildings 

 should also be so regulated that those opposite them 

 are not in perpetual shadow. 



NO. 2648, VOL. 105] 



The Empire Timber Exhibition. 



By Alexander L. Howard. 

 /PHE Overseas Trade Department of the Board of 

 ^ Trade some time ago conceived the idea of 

 organising an exhibition which should be a representa- 

 tive collection of those timbers which form the forest 

 wealth of the countries which constitute the British 

 Empire. This excellent scheme, possibly the direct 

 outcome of the experiences of the war, was cordially 

 and unanimously supported by the representatives of 

 the Governments overseas. 



Among the many lessons learned as a result of the 

 war none was of greater importance than the know- 

 ledge that was brought home to us of our great 

 dependence upon the products of the forest for the 

 making and building up of every possible kind of 

 offensive and defensive engine of warfare as well as for 

 the maintenance of the daily requirements of ordinary 

 life. From the time when the proposals of the Board 

 of Trade were first considered every eifort was made 

 by the representatives of the different States of the 

 Empire and by the officials at home to see that not a 

 stone was left unturned to show conclusively what it 

 was possible to achieve in the matter of timber pro- 

 duction from every source. By a happy chance the 

 date for the exhibition was fixed to coincide with 

 that of the British Empire Forestry Conference, which 

 brought together representatives of the Forest Services 

 throughout the Empire, and there can be no doubt 

 that such an exhibition must form the best possible 

 opportunity for the forest man to gauge the value of 

 the work upon which he is engaged. 



The countries of the world may be classed into 

 three grades : one which possesses a competent 

 scientific forest service with practical work in full 

 operation ; a second which also possesses such a forest 

 system, but lacks the practical application of theory; 

 and a third which possesses neither scientific nor prac- 

 tical forestry. It is regrettable that until a very recent 

 date the United Kingdom must have been classed in 

 the last category, and, although much has been done 

 in the past few years to remedy the situation, it is 

 doubtful whether the great national importance of the 

 subject has yet been fully realised. 



The Empire Timber Exhibition entailed an enormous 

 amount of continuous hard work and persistent 

 energy which eventually resulted in bringing together 

 a collection of many hundreds of timbers from every 

 part of the Empire, and certainly the majority of those 

 of any commercial importance. A collection of this 

 kind is not easy to gather together, and it is doubtful 

 \yhether such an opportunity is likely to be again 

 available for a very long time. 



The following are a few of the more noteworthy of 

 the exhibits of the various countries : 



British East Africa. — The considerable forest re- 

 sources of this country are practically unknown 

 and their exploitation is yet in its infancy. The 

 most important timber is pencil cedar (Juniperus 

 procera), which is slightfy harder and more brittle 

 than the American variety (/. virginiana). So far it 

 has not been much appreciated by British manufac- 

 turers, although its importance may be gauged from 

 the fact that in 19 10 31,000 logs of this timber were 

 imported into Germany ifrom what was then German 

 East Africa. As the majority of the lend pencils 

 used in this country before the war were of German 

 manufacture, the importance of this supply is obvious. 



The Gold Coast. — Supplies of the timbers of the 

 Gold Coast have already been seen in this country, 

 but this exhibit showed many which are unknown 

 here, though, as with other countries, much confusion 



