Reviews and Book Notices. 
IOI 
a number — a coefficient, analogous to the ‘ soil-moisture coefficient ’ 
given by the ratio , and it certainly does ‘ express ’ though it in 
no sense ‘ gives,’ the humus content of a soil. What its value as an 
‘ expression ’ of humus content may be we need not discuss, since Mr. 
Crump has already said that he does not regard it as ‘ a matter of any 
importance,’ and has explained why he found it convenient.* 
Mr. Johnson asserts (page 436) that ‘ the defence of this equation 
involves the accuracy of the whole paper. . . . We now find that the 
cardinal point of the whole paper — humus-content — rests on uncertain 
ground.’ This is an erroneous assertion. There is no question of defending 
an equation which has never been put forward, and if there were it 
would not ‘ involve the accuracy of the whole paper,’ because it has 
nothing to do with the main subject of the paper (abstract). The 
ratio is mentioned only in a final line as quite a separate thing, and the 
water ratio does not depend upon it in any way whatever. 
In defending his own simple, and (as Mr. Crump admits) literally 
true statement that ‘ peat usually contains 80 to 90 per cent, of moisture, 
and when air-dried 15 to 25 per cent.,’ Mr. Johnson refuses ‘to enter 
into a discussion of the accuracy of such a well-known and generally 
accepted scientific fact.’ No one has impugned its accuracy. Mr. 
Crump expressly says the statement is literally true. On the other hand, 
to say that ‘ the suggested changed standard of comparison is purely 
imaginary ’ is to deny flatly the obvious fact that in one case the 
standard is wet peat, and in the other case air-dry peat. Both quantities 
(of water) are percentages, but they are percentages of different totals. 
What is that but a changed standard of comparison ? 
Those interested in the subject will find a full account of Mr. Crump’s 
method, and of the striking results that can be obtained by it, in ‘ The 
Coefficient of Humidity : a New Method of Expressing the Soil-moisture ’ 
(Xew Phytologist, Vol. XII., 1913, pp. 125-147). 
Botany School, Cambridge. A. G. Tansley. 
— : O : — 
The Bodley Head Natural History. By E. D. Cuming, with illustrations 
by J. A. Shepherd. Vol. 2. British Birds, Passeres. London : John 
Lane, 1914, 122 pp., 2s. net. This volume has all the charms and attri- 
butes of its predecessor, recently noticed in these columns. It deals 
with White throats. Warblers, Wrens, Hedge Assentors, etc. The scores of 
illustrations and general ‘ get up,’ are all that can be desired. 
A History of Threekingham-with-Stow, in Lincolnshire, attempted 
by W. A. Cragg. Sleaford : W. K. Morton & Sons. 155 pp., price 6s. net. 
Like every other place, Threekingham has a history, and in this book the 
author has modestly ‘ attempted ’ to record that history, so far as he has 
been able to read it. It is divided into sections under the headings of 
our various reigning monarchs, under each of which Mr. Cragg has re- 
corded everything he has been able to find. Naturally they vary- a good 
deal; for instance, under James II. we find half-a-dozen lines only, record 
ing that one Edmund Hutchinson gave a sundial, now on the church 
porch, etc., whereas under ‘ William and Mary,’ there are several pages. 
There is the usual story of the horrors of ‘ restoration ’ of the church. 
There is an interesting botanical note, circa 1793, and a long list of plants on 
* a bank by the roadside about 100 yards long, whereon grows the greatest 
variety of herbaceous plants that I have ever met with in so small a com- 
pass before.’ There is a very unusual chapter on ‘ Lincolnshire weather 
in a.d. 1330 and a.d. 1790 contrasted ’ ; there being in existence two 
journals of the weather for these periods. Mr. Cragg has done a distinct 
service in preserving the various records in his history. 
1914 Mar. 1. 
* Naturalist, June 1913, p. 241. 
