May 22, 1902] 
NATURE 
7S 
may obtain the prize ; he must dig and drain and enrich 
the soil, must plant, protect and prune, and, like the 
husbandman, he must have long patience before the 
harvest comes. He must be prepared for failures and dis- 
appointments, for nipping frosts and scorching suns, hail- 
stones and drenching rains, for blight and mildew, 
fungus and thrip, for aphis and grubs, spiders and 
beetles, suckers and weeds. The obstacles are many, 
and the enemies are fierce, as ever to those who would 
attain excellence. 
But perseverance will prevail, and he who has an 
expert for his guide will reach the summit, however 
steep may be the mountain. He who has a productive 
soil, a situation sheltered but not overshadowed, an 
atmosphere not polluted by smoke or smut, who adds to 
these inseparable adjuncts of success a determination to 
succeed, and then follows, in strict obedience, the teach- 
ing of Mr. Foster-Melliar, will repeat his achievements ; 
the pupil will become a professor, and the entered 
apprentice will be a master-mason. 
On the subject of “garden roses,” roses which have 
not the perfect symmetry and fulness required for ex- 
hibition at our shows, the author declares that he is no 
authority, and he tells us little or nothing of their infinite 
variety and beauty in beds, borders and shrubberies, 
on pillars, pergolas and walls ; but as a manual for the 
production of those roses, which have been most admired 
by rosarians, in their loveliest form, his admirable essay 
is complete. 
OUR BOOK SHELF. 
The Birds of North and Middle America. Part i. “ The 
Fringillide.” By R. Ridgway. ABudletin U.S. Museum, 
No. 50. Pp. 715; 20 plates. (Washington, 1901.) 
Mr. RipGway is such a well-known authority on the 
birds of North America that anything coming from his 
pen is sure to obtain a welcome at the hands of his 
brother ornithologists. The size of the present volume, 
which, as stated in its title, deals only with a single 
family, affords an index of the bulk and extent of the 
work of which it forms thecommencement. The amount 
of labour involved in such a task is enormous and can 
only be properly appreciated by working naturalists. 
Preparations for the work, the author tells us, have been 
in more or less active progress for the last twenty years, 
and so long ago as the autumn of 1894 the task of putting 
together in proper form for press the vast accumulation 
of material was taken in hand. The labour of measuring 
specimens of more than 3000 forms of birds and making 
the necessary references to previous descriptions was, 
however, so vast that it has only been possible to issue 
the first part after this long lapse of time. It is hoped, 
now that much of the drudgery is accomplished, future 
progress may be more rapid. 
The object of the work is to describe in detail every 
definable form of bird—whether species or subspecies— 
met with on the American continent, from the Arctic 
districts to the eastern end of the Isthmus of Panama, 
together with the West Indian and Galapagos Islands. 
Moreover, besides the indigenous denizens of the area, the 
accidental or casual visitors, as well as artificially intro- 
duced species, are included, so that the list is as full and 
comprehensive as possible. Needless to say, the work 
is written on modern American lines, so that the number 
of forms regarded as entitled to distinction is very great ; 
while the number of genera and subgenera is likewise 
NO. 1699, VOL. 66] 
unusually large. An especial feature of the work is the 
large number of forms which are relegated to the rank of 
subspecies. 
As regards the description and keys to the different 
groups and species, the work appears to be admirably 
written, the number of specimens of which the measure- 
ments are given rendering it especially valuable. Perhaps 
it was somewhat unnecessary to give a general account 
of birds and their various orders, but this is a fault on the 
right side, and the work should prove invaluable to all 
zoologists on both sides of the Atlantic. In replacing 
the name “‘ Central America” by the unfamiliar ‘“ Middle 
America” the author may be etymologically right, but if 
this be the reason of the innovation, it is somewhat 
curious to find such a change advocated by American 
naturalists, who are notorious for the contempt with 
which they treat the synthesis and orthography of 
scientific names. IG Lp 
The Lens. A Practical Guide to the Choice, Use and 
Testing of Photographic Objectives. By T. Bolas, 
BP.C.S:, }.15C., jand (George: E. Brown, FIC; Pp. 
vi+176. (London: Dawbarn and Ward, Ltd., 1902.) 
Price 2s. 6d. net. 
THIS is a useful book, not only for beginners in the use of 
the camera, but for many photographic workers who have 
never studied the optics of lenses. The elementary 
treatment of lenses is far in advance of that of most 
professed English text-books of optics, as from the outset 
it does not make the assumption of an infinite thinness of 
lenses, but treats them by the method of Gauss by means 
of principal planes and principal points. Unfortunately, 
the authors persist in calling the principal points “nodal” 
points, a confusion of language which will puzzle students 
if when they come to the eye they discover that the 
nodal points of that organ are not the same as the prin- 
cipal points. There are good discussions of the subjects 
of angle of view, inequality of illumination and “depth 
of focus.” We are. glad to see that the authors have 
summoned up courage to omit “indigo” from the tints of 
the spectrum. It has long been recognised that there is 
no indigo tint between the blue and the violet. It is a 
pity that the authors admit the vulgarism in chapter iv. 
of writing the aperture-ratios 7/24, f/16, &c., as 24, 
716, &c. On p. 49 they give the notation correctly. The 
lens diagrams would be improved by cross-hatching the 
sections of the lenses ; it is impossible by looking at the 
mere outline, for example, of the composite back lens of 
Fig. 104A, on p. 91, to tell whether it represents three 
lenses cemented together or two lenses separated hy an 
air-space. The practical hints on focussing, copying 
and enlarging are excellent ; and we quite concur in the 
advice on p. 95 to avoid second-hand lenses. Some 
admirable examples of the performance of lenses are 
reproduced in half-tone blocks. That of King Henry VII.’s 
Chapel on p. 171 is really marvellous. 
A Text-book of Geology. By Albert Perry Brigham, 
A.M., F.G.S.A., Professor of Geology in Colgate 
University. Pp. 477 ; illustrated. (London: Hirsch- 
feld Brothers, Ltd., 1902.) 
ALTHOUGH this work bears on its title-page the 
name of a London publisher, it is evidently pre- 
pared with a view to the requirements of teachers and 
students in the United States. It forms one of the 
“Twentieth Century Text-books” edited by Dr. A. F. 
Nightingale, formerly of Chicago. According to .its 
authors preface, this text-book has been especially 
prepared as an elementary treatise for secondary schools 
in America, and it seems admirably adapted for this 
purpose. While modestly disclaiming any great origin- 
ality in the plan of the work or novelty in the mode of 
treatment of geological problems, the author may be 
