Ixvl. PRESIDENT'S ADDRESS. 



site obtained with a considerable variety of ground, so that 

 it is hoped that most of the South African plants can be 

 successfully cultivated. The identification of different kinds 

 of wood is an exceedingly difficult matter, except in a few 

 cases, which fact I am led to allude to by the publication of a 

 book on the Cabinet Timbers of Australia, which are said 

 to be, as I have before understood, very beautiful and varied. 

 More than 60 species are illustrated by colour photography, 

 it is stated with great success. The recent issue of a book 

 on Herbals, which ought to commend itself to both sides 

 of our Club, causes me to remind you of a book much more 

 closely connected with us, written by the Hon. Mrs. Evelyn 

 Cecil, " A History of Gardening in England," which contains 

 an immense amount of reliable and pleasantly-written infor- 

 mation about these entertaining old books, as well as much 

 else besides. We shall always remember her kindness and 

 botanical lore on the occasion of our visit to Lytchett Heath 

 in 1907. 



GEOLOGY. 



The last suggestion for calculating the age of the earth is 

 the measurement of the amount of meteoric dust contained 

 in the rocks, basing this on the amount of nickel. It is 

 calculated that the earth gains 20,000 grams (about 451bs.) 

 of cosmically derived nickel per square kilometre per annum, 

 which sounds an improbably large amount, as it means some- 

 thing like 1 grain per annum on each 3 square yards, but the 

 actual calculation of the earth's age requires more data than 

 are at present available. The calculation based on the in- 

 crease in the proportion of lead to uranium in rocks as time 

 goes on, the uranium changing slowly into lead, gives a very 

 early date for the earliest sedimentary rocks of 1,300,000,000 

 years ago, about 4 times as much as some other methods. 

 The observation of earthquakes, if the deductions may be 

 relied upon, tends to throw light upon the constitution of the 

 earth's interior. Earthquake waves from different distances 

 travelling in a direct line to any observatory necessarily 





