+ 
Avebury must be the older because it exhibits no mark of 
tools such as we see on Stonehenge. I must ask you to forget 
for the time all ideas you may have formed about the Belge or 
the Druids, or the Saxons, or the Britons, or the age of Agricola, 
or the supposed age of the tumuli which abound near Stonehenge. 
I must ask you for this afternoon simply to follow the reasoning 
and the calculations I shall have the honour of submitting to you, 
and not to allow yourselves to be disturbed by any anxiety on 
account of the early date for Stonehenge to which my theory 
points. 
That date Iam obliged, by astronomical considerations, to fix at 
least 2,800 years before the present year 1897, 7.2. B.c. 900, 
more than 1,000 years before the death of the great man and 
famous general, Agricola, in whose time and under whose auspices. 
some writers have thought Stonehenge may have been built. 
TRUE LENGTH OF THE YEAR UNKNOWN TO THE ANCIENTS. 
I have asked you to put yourselves into an open frame of mind 
by dismissing preconceived ideas. I further ask you to endeavour 
to realise in your minds the state and condition of mankind in 
and about the age I have mentioned as regards one branch of 
human knowledge, one, too, of immense importance in the affairs 
of men. It may seem difficult for us, who every Christmas are 
inundated with Almanacs of every description, to realise that 
during many successive ages all the peoples of the world lived 
in ignorance as to the exact length of the solar year. But. 
so it was, and the most intelligent intellects of the more 
advanced nations of the earth were engaged on the attempt to. 
solve this great problem. In the time of Herodotus the 
Egyptians had come nearest to the truth.* They had found by 
prolonged observation of the stars in connection with the Sun that 
the solar year contained 365 whole days. But other nations 
did not reckon the length of the year by this standard, with which 

* Herod. Hist., Bk. II., Chap. iv. 
