34 6 



NATURE 



{Feb. 12, 1880 



Duchy of Cornwall ; vitriol is the fume given off by heated 

 sulphur ; and the refinery in the tin-plate forge is only a 

 meltino'-furnace. Altogether the author treats the South 

 Wales°forge process, one of the most subtle and delicate 

 in the whole range of iron metallurgy, somewhat scantily. 



H. B. 



Mathematical Tables, chiefly to Four Figures. First 

 Series. By James Mills Peirce, University Professor 

 of Mathematics in Harvard University. (Boston, U.S. : 

 Ginn and Heath, 1879.) 

 This is a well-arranged and clearly printed book of forty- 

 three octavo pages. Besides four figure logarithms of 

 numbers and of circular functions, and the circular functions 

 themselves, it contains a table of logarithms of hyperbolic 

 functions, occupying three pages, Gaussian logarithms of 

 sums and differences, inverse circular functions (the argu- 

 ment being the log. sine, &c), and a special table for 

 finding the logarithms of circular functions of small angles, 

 which is to be used by reducing the angle to minutes, and 

 then adding its logarithm to a logarithm given in the table. 

 There is no table of antilogarithms, but it is not needed, as 

 the logarithms of numbers extend over more than a 

 complete c>cle, beginning with the number 100, and 

 ending with 1999, so that the differences between succes- 

 sive logarithms are always small. A saving of space, 

 ■without loss of utility, has been obtained by carrying the 

 proportional parts only as far as 5 instead of to 9 as usual. 

 This involves subtraction for 6, 7, 8, and 9, but the 

 quantity to be subtracted is so small that the operation 

 can be performed mentally. The sixteen pages of " Ex- 

 planation of the Tables," including a page and a half on 

 Hyperbolic Functions, are remarkably clear and good. 

 ™ J. D. E. 



Eight Mouths in an Ox Waggon. By E. F. Sandeman. 



(London : Griffith and Farran, 1S80.) 

 Mr. SANDEMAN has written a most interesting volume 

 on his experience in South Africa. His party made 

 their expedition to the Transvaal in an ox waggon. It is 

 the ttory of their adventures, during the time they were 

 hunting there, that is told in this volume. The book is, 

 however, by no means a diary of the daily doings in the 

 Transvaal. It abounds in reminiscences of Boer life, and 

 accounts of the natural history of the country. In the 

 latter respect Mr. Sandeman has shown that he is a good 

 observer. We can only give a few extracts. Speaking 

 of ant-bears, he says : — 



" The holes of the ant-bear are sometimes five or six 

 feet deep, and large enough to engulf horse and rider ; 

 but as they are generally conspicuous, they do not prove 

 so dangerous as the smaller holes of the mere-cat, a pretty 

 little animal between a rat and a stoat, found all over 

 South Africa." 



The various changes in the bird and insect-life in the 

 Transvaal, as the day passes on, seems to be very much 

 marked and curious. " As the heat of the day comes on, 

 the game of all descriptions retiris to the shade, and is 

 neither to be seen nor heard, and the air is full of 

 gorgeous insects of every size and colour, from the large 

 butterfly, flitting from reed to reed, to the sphinxes and 

 sand-flies, whose movements as they dart and glance 

 through the sunlight are too quick for the eye to follow. 

 Darting after these, and glancing like little bolts of shiny 

 gold or silver, set with emeralds and rubies, are innumer- 

 ably brilliantly plumaged small birds, who again retire 

 into the reeds when the butterflies shut up their wings as 

 the heat of the sun ceases to warm them into activity. 

 But the cooling atmosphere is far from being tenantless ; 

 for, as the sun goes clown, myriads of clear-winged long- 

 bodied flies swarm up from the ground, and after ihe_-e 

 there dart out from their hiding-places of the day a 

 devouring crowd of black-birds with white tails, who 

 gobble up the flies by the dozen. A large kind with gold 



feathers in their wings also assist at the banquet ; and a 

 smart little wagtail has a larger share perhaps than either 

 of the others, for he is quicker in his movements, and 

 never misses his dart. When these go to bed later on, 

 owls, night-hawks, bats, crickets, frogs, and jackals, 

 combine to break the stillness of the night with their 

 harsh discordant cries and croakings." 



Farther on in the book we have a long account of how 

 a honeybird led the author and his friends to find honey. 

 From the description one must think this bird had 

 reasoning powers almost human. Throughout the book 

 are descriptions of the scenery of the country. We only 

 quote one paragraph : — 



" The scenery became wilder as we advanced. The 

 hills were loftier and more broken up, and here and there 

 covered up with thick brushwood. The veldt itself was 

 strewn with quartz rocks, and rugged boulders. The 

 streams were full of beautiful quartz pebbles worn 

 smooth by the constant friction. Many of the rocks have 

 streaks of pure iron in them, and on every side are relics 

 of the volcanic action, which must have formed the 

 greater part of the Transvaal." 



The book is written in a simple and attractive style. 

 It will be of considerable interest to naturalists and to 

 those who may meditate a similar hunting expedition in 

 the Transvaal. We would recommend it as an interesting 

 and instructive record of a holiday. It contains a large, 

 useful map of the Transvaal and the surrounding terri- 

 tories. 



The Countries of the World. By Robert Brown, M.A. 



(London : Cassell, Petter, Galpin, and Co., 1879.) 

 The present volume of " The Countries of the World" is 

 devoted to Polynesia, Australasia, Malaysia, and Japan. 

 The people who inhabit these islands having been fully 

 discussed in another volume, there is only a brief sketch 

 of them given here. The author, in his compilation, 

 takes us first through the Polynesian islands, gives a 

 general idea of the plants and animals peculiar to them, 

 short accounts of the mode of government and the pre- 

 sent state of the country. All this is done in a pleasant 

 and interesting manner. New Zealand, Australia, and 

 Japan are treated in the same way. Our Australian 

 colonies are described more fully. The numerous illus- 

 trations throughout the book will be a great attraction to 

 it. They are very well done. 



LETTERS TO THE EDITOR 

 {The Editor does not hold himself responsible for opinions expressed 

 by his correspondents. Neither can he undertake to return, or 

 to correspond with the writers of, rejected manuscripts. No 

 notice is taken of anonymous communications. 

 [The Editor urgently requests correspondents to keep their letters as 

 short as possible. The pressure on his space is so great that it 

 is impossible otherwise to ensure the appearance even of com- 

 munications containing interesting and novel facts.\ 



Light of Webb's Planetary Nebula (DM. + 41" 4°°4) 

 The recent discovery by the Rev. T. W. Webb, that the star 

 DM. + 41° 4C04 is a planetary nebula, and the attention which 

 has consequently been atlracted to this object, induce me to send 

 herewith the result of a measurement of its light made at the 

 Harvard College Observatory. Observations are in progress 

 upon the light, dimensions, and spectra of all known planetary 

 nebulae visible in this latitude. To avoid the repetition of similar 

 errors, two or three observers take part in the work, and each 

 makes only one series of observations upon the same nebula in a 

 single evening. . , 



The photometric measurements are made by throwing the 

 ima^e of a star out of focus to such an extent that its intrinsic 

 brightness becomes apparently equal to that of the nebula which 

 is simultaneously observed with the same eye-piece, i-ach 

 determination consists in six comparisons made alternately inside 

 and outside of the focus of the auxiliary telescope through w hich 

 the star is seen. The light of the nebula is expressed by the 



