KEYIEWS. 
413 
then are the following in accordance with the river-basins : 1. Upper Colne ; 
2. Lower Colne; 3. Cran ; 4. Upper Brent; 5. Lower Brent; C. Lea; 
7. Metropolitan. The authors^ to give perfect uniformity to their scheme, 
even put down the last-named district as drained by the Fleet, West- 
bourne, Wall broolf,” &c., but we fear that even this will hardly convey a 
satisfactory idea as to the metropolitan district being a river-basin or series 
of river-basins. The plan of the Flora is simple. The orders are given as 
in Babingtou’s Manual, the genus following as a sort of heading ; the 
species then follows in black-faced type, and when it has a genuine verna- 
cular name this is given also. Then comes the synonymy, and lastly 
references to the page in Watson’s Cyhele, and in Syme’s English Botany, 
where the plant’s distribution is stated, and where it is figured. In the last 
paragraph it is mentioned whether the plant is very common, common, rather 
common, rather rare, rare, or very rare. The lists of Cryptogamia, with 
the exception of the ferns, are very meagre, but the authors did not purpose 
to deal with them at all, and have merely given them in form of an appen- 
dix. The map, which is a geological one, on which the districts are dis- 
tinctly indicated, is of good size. The index is full, and the list of corrections, 
we are glad and sorry to say, is somewhat extensive. Altogether the Flora 
deserves the highest praise, and we hope it may reward its authors for the 
many months of work it has given them. 
CHEMICAL ARITIBIETIC.^ 
S tudents in chemistry who go up for examination to the London 
University are too often painfully aware that many of the questions 
involve arithmetical calculations. Singularly enough, however, exercise in 
such calculations are generally omitted from our best books on chemistry. 
It has been Mr. Woodward’s aim to meet this want, and we think he has 
been successful. He has issued his exercises in a series of printed cards 
enclosed in a sort of map-case. We question the wisdom of this, as the 
tables now run the chance of being torn or lost, which they would not do 
if in book form. On the other hand, it must be admitted that in the 
present form they are very handy and portable for the student. The exer- 
cises are ten in number, and relate to the following subjects, the importance 
of which will be at once seen by the industrious student : — The metric 
system ; thermometer scales and pressure of gases ; specific gravity ; per- 
centage composition of a body deduced from its formula ; empirical formula 
deduced from percentage composition ; quantity of material required to 
yield a given weight for substance ; estimation of volume in certain decom- 
positions ; combination and decomposition of gases or bodies in gaseous 
form ; the crith and its uses, and thermal units ; and lastly, specific, atomic 
and latent heat. We do not hesitate to say that every student of chemistry, 
whether purely scientific or medical, sliould purchase these tables, and 
* Arithmetical Exercises for Chemical Students.” By C. J. AVoodv ard, 
B. Sc. London : Simpkin and Marshall. 1869. 
