April 2, 1908] 



NATURE 



513 



tirilc iiiosl cxccUontly the ornitholojjical characters of 

 Yoiksliiic. The crrnln, in which there is a curious 

 misprint, is not quite complete, and omits to state that 

 laser spotted woodpecker should be greater (p. 276), 

 and blue tit should be great tit (p. 114). There are 

 two indices, but unfortunately no map. 



The latest work on the birds of Kent (which 

 from its title, indeed, does not claim to be a 

 complete history of the subject) is founded on the 

 material brought together in connection with a 

 certain area of that county; but in that limited por- 

 tion of the county it was noticed that the avifauna 

 would scarcely be of sufficient importance to fill even 

 a small work. It was therefore found advisable to 

 take in the whole of the county. It was also thought 

 desirable to collect all the material hitherto written, 

 and give to those who have done so much towards our 

 knowledge of the birds of Kent full credit for their 

 observations. This has in the main been carried out, 

 and the result has been a compilation giving us a 

 great deal of information about the birds of Kent. 

 Indeed, so anxious have the authors been to give all 

 possible credit to those who have written anything 

 about the local ornithology that they have been misleo 

 into including in their book a number of notes and 

 observations which were not worth reproduction, and 

 the discursiveness of which has made it extremely 

 difficult to arrange the facts in the present work in an 

 orderly and systematic manner. In fact, the book is 

 very well described by its title, and although the 

 reader has never been led to expect a systematic his- 

 tory (from a local point of view) of the birds of Kent, 

 the book is a storehouse of facts relating thereto. 



W'e should have been glad to have a complete 

 book on the subject to fill up a blank in the county 

 bird-book shelf ; a volume with more personal observ- 

 ations from the authors, and a compilation more com- 

 plete. The present volume has not been brought 

 up to date. For instance, a valuable paper pub- 

 lished in the Zoologist so long ago as February, 

 1907, has been quite overlooked. Had this been con- 

 sulted the sheldrake might have been added to the list 

 of ducks breeding in Kent, while the status in the 

 county of the shoveller and some other ducks, as given 

 in the volume under notice, would have been some- 

 what modified. Nor has the information relating to 

 the various birds always been brought down ev-en to 

 recent years. 



Concerning the guillemot breeding on the Kentish 

 coast, we have a description of the breeding colony 

 in St. Margaret's Bay, written so long ago as 

 1852, and a note on the same made in 1S87, but 

 nothing more recent in the way of exact information 

 about the bird breeding on the coast at the present 

 day, although we are told that the bird is, during 

 the summer and breeding season, very numerous. It 

 would surely have been worth the while of one of 

 the authors to ascertain the exact conditions of the 

 breeding place or places after the lapse of twenty 

 years. This is only one instance out of several. 

 .■Kgain, on turning to the articles on the birds more 

 particularly associated with Kent, we find that the 

 greater part of that on the Sandwich tern consists 

 of matter written in the eighteenth century, and we 

 are left in doubt as to whether this bird still breeds 

 annually on the coast or not. 



The article on the Kentish plover is more satisfying, 

 although it consists almost entirely of quotations (ex- 

 cellent in themselves), with no qualifications, remarks, 

 or annotations by the authors. An exact statement of 

 the status in Kent of each bird would have been 

 welcome. Kent is credited with a list of 320 species, 

 bu' of these the black grouse is stated to have long 

 been extinct. We cannot quite follow the authors in 



NO. 2005, '^''^L 77] 



their application of this word when they go on to 

 say that many of the birds, which might also come 

 under the same word, such as the crane, bustards, 

 cream-coloured courser, &:c., are likely to become 

 occasional visitors, although comparatively extinct in 

 the county (italics ours). There are certainly no 

 grounds for calling the last-named bird " extinct " in 

 the county, as it has never been anything more than 

 a purely accidental straggler to these islands ; while 

 the other two species are absolutely, and not only 

 comparatively, extinct as native birds in Great Britain, 

 although they may occur from time to time as 

 visitors. .Speaking of the rarer visitors to Kent, the 

 authors remark on one very extraordinary circum- 

 stance, viz. that a very large number of the rare 

 seed-eating and other birds should have been found 

 on the Sussex coast, whereas none of thern have been 

 observed in the adjoining county of Kent; and the 

 suspicion here expressed that niost of these birds have 

 been introduced by human agency has certainly been 

 entertained by many people. 



The introduction contains an excellent topographical 

 account of this maritime county (with its 140 miles of 

 coast lapped by tidal water) and its natural features. 

 There is an index, and a map of a handy size and 

 sut'ficient for its purpose. The frontispiece to this 

 well-got-up volume is a picture from a photograph 

 of a bit of woodland with a woodcock on her nest, 

 and is one of the most beautifully executed and 

 successful pictures of this kind we have ever met 

 with. The difificulty in at first seeing the sitting 

 bird, and the failure of the eye to pick it up at once 

 jn again glancing at the picture, as well as the way 

 the figure and details of the bird seem to grow on 

 the sight when once it is located, or located once more, 

 is an admirable representation of the real f.icls of 

 such cases. The other eight full-page plate^ di-ijict 

 birds — like the masked shrike, which has only occurred 

 once in Great Britain— especially associated with 

 Kent, and (especially the one named) are very wel- 

 come. But they would have been more useful had 

 they been more correctly coloured. The wing coverts 

 of the lesser kestrel should not have been grey, and 

 the legs of the avocet should have been bluish-grey 

 and not olive-green, a colour which has been also 

 used for the legs of the Kentish plover instead of the 

 correct black or brownish-black. Ornithologists will 

 be glad to have the voluminous literature relating to 

 the birds of Kent collected in this nice-looking volume, 

 the paper, binding, and general get-up of which do 

 the publisher great credit. 



MODERN NITKE BEDS. 



EVER since the invention of " villainous saltpetre," 

 the provision of a sufficiency of nitrates has been 

 one of the preoccupations of a ministry of war, and 

 the necessity has become greater rather than less 

 under the conditions of modern warfare. The potass- 

 ium nitrate that was required for the fabrication of 

 gunpowder is now replaced by the nitric acid used in 

 making the various types of nitro-explosives, but it is 

 always the nitric ion that has to supply the oxygen, 

 and the consumption in a modern battle attains a 

 magnitude of which our immediate predecessors using 

 black powder had no conception. Indeed, one truly 

 scientific argument against war may be drawn from 

 the enormous losses it occasions in the world's limited 

 stock of combined nitrogen. 



Up to the middle of the nineteenth century, India 

 was the only source of nitrates on a large scale, and 

 though a certain amount of nitre was recovered from 

 the efflorescence of the walls of cellars and from arti- 

 ficially made beds of earth mixed with decaying animal 



