THE FLORA OF WARWICKSHIRE. 
157 
E. Peplus, Linn. Petty Spurge. 
Native: In cultivated land, by roadsides, and on waste heaps. 
Common. March to October. Area general. 
E. exigua, Linn. Dwarf Spurge. 
Colonist: In cornfields and on bushy roadsides. Locally common. 
June to November. 
I. Cornfields near Sutton; Middleton; roadsides near Penns; Shu stoke; 
Arley ; Coleshill; Marston Green; Solihull; Olton ; Sheldon, etc. 
II. Opposite Stoneleigh Lodge; open field between Harbury and Tacli- 
brook, Perry FI., 42 ; Salford Priors, Rev. J. G. ; near Harboro’ 
Magna; Little Lawford; Cubbington; Stoneleigh, Wilmcote; 
Oversley; Alcester; Ragley. 
Uncertain in its occurrence, often absent for two or three seasons 
in any given station. 
[. E . Cyparissias, Linn., is recorded in the Rugby School Report from 
near Rugby, but was merely an escape.] 
MERCURIALIS. 
M. perennis, Linn. Perennial Dog's Mercury. 
Native: In woods, copses, and shady banks. Common. February 
to April. Area general. 
[Buxus sempervirens, L., occurs occasionally in hedges and woods, 
but only where planted.] 
CERATOPHYLLACEAE. 
CERATOPHYLLUM. 
• 
C. aquaticum, E. B. Common Hornwort. 
Native : In pools. Rather rare. 
I. Berkswell mill pool! Herb. Perry; pool near Berkswell Hall; pools 
at Springfield and Temple Balsall. 
IT. In a stew of the Rev. Mr. Bree’s, Allesley, Purt. iii., 70; Chesterton 
Mill Pool! St. Nicholas Mill Pool, Herb. Perry; Caludon House 
Wood, near Coventry, T. K ., Herb. Perry; Old Canal, near 
Brown’s Over, R. S. R., 1868; Burton Dassett, Y. d B.; Itching- 
ton Holt; pool by Oakley Wood; cattle pool near Gay don Inn ; 
in flower, Sowe Waste Canal, 1883. 
(To be continued.) 
WEIGHING THE EARTH WITH A CHEMICAL 
BALANCE. 
The various methods by which the density of the earth, 
and consequently its weight, have been ascertained, are all 
dependent upon the principle of comparing the pull, or attrac¬ 
tion, of the earth upon some small body with that exerted 
upon the same body by some mass of definite size and weight. 
From reasons which are not known to us, Newton arrived at 
the conclusion that the earth was between 5 and G times 
