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XATURE NOTES. 
ordinary reader, but they might well have been more numerous. The work is 
worth perusal, but it can hardly claim a permanent place upon the Selbomian 
bookshelf. 
Science Ladders, by X. Dk\nvers. 5 vols., 8vo. London ; Geo. Philip & 
Son. i/- each. This is a series of simple reading-books giving lessons in physical 
geography, natural history and geology. They are quite elementary in their 
scope, and are written in sufficiently simple language for any intelligent child to 
understand ; at the same time they show every sign of careful preparation, and 
are generally trustworthy. They are much superior to any science te.xt-books of 
an equal standard with which we are acquainted. The first volume is on The 
Earth and its Early Explorers, giving in 146 pages a simple account of the most 
striking phenomena of physical geography, and a sketch of the history of early 
exploration ; this is one of the best of the series and except for an occasional intro- 
duction of catastrophes (e.^., pt. ii., p. 10) and an antiquated theorj- of the causes 
of the ocean currents, there is little to object to. The second volume on 
Vegetable Life and its Lxreeest Forms is far less satisfactory : the author in more 
than one place defines and uses ovule as equivalent to seed, and defines dry seeds 
as those that burst their envelopes. He says that the old leaves of Sigillaria 
formed the trunk ; that water is a “ mixture ” of hydrogen and oxygen. On p. 32 
he states that “ the stomata are most numerous on the upper side of leaves which are 
exposed to the air,” whereas, those that grow straight up have them on both sides, 
and those under water only on the lower side ; but the confusion of fact is perhaps 
a mere matter of detail, since it enables the author to draw a sound moral as to 
the benevolence of such a providential arrangement of things. The definitions 
are generally couched in simple language, so simple in fact, that it is often quite 
impossible to tell what is meant, as when (pt. i., p. 16) the nucleus is defined as 
“ so-called because, like a nut, it holds the kernel or the heart of a plant,” or when 
(pt. ii. , p. 2c) the author points out that “ fungi are more like animals than plants 
in their volatile parts.” It is to be regretted that in the chapter on lichens no 
hint of symbiosis is given. Volume III. deals with Lx>-,uly Water A/iimals, some 
of which Mr. D’Anvers makes a good deal lowlier than they are, as when he 
places (p. 31) the sponges in the Protozoa and much lower than the Infusoria. 
It would be quite easy to pick out many small mistakes in this, as in the other 
volumes, but perhaps the most serious is that the figure on page 20 of part ii., 
which is said to be a ship-worm is really a Pholas. The author is often happy 
in his choice of simple illustrations, but his name for rotifers of “ tiny creatures 
with water-works ” is not one of these, as the term would have been far more 
aptly applied to the water vascular vessels of the echinoderms. The fourth 
volume on The Life Story of our Earth is an improvement on the last, though 
the frontispiece of a labryinthodon without any tail is a bad start, especially as 
the author correctly states in the text (p. 71) that they had long tails ; the state- 
ment on p. 14 that the earth has “ a coder outer crust of luatery matter ” is not a 
model of precision. 
The last part is devoted to The Story of Early Man, and is a pleasantly written 
sketch of the elements of the subject ; that most of it is a compilation and not 
based on personal knowledge is shown by such mistakes as that the altar stone at 
Stonehenge is of “ blue marble ” instead of red sandstone, and that at Abuiy there 
are t-jco stone avenues leading to the circles. The statement that “ during the 
glacial period the centre of North America was one great lake .... [which] 
became broken up into the now well-known group of five great sheets of water, 
of which that of Niagara is one ” shows that the author understands the pleistocene 
geology of North America as clearly as he does the difference between a waterfall 
and a lake. J. W. G. 
