io6 



NATURE 



\yune lo, 1875 



The following explanation of the reaction occurring 

 during the immersion of the collodionised plate in the 

 nitrate bath is given at p. 41 : " The salts of iodine and 

 of bromine that exist in the collodion film change their 

 properties with nitrate of silver and give birth to iodide 

 and bromide of silver and to 7ntric acid salts." The 

 italics are our own. On p. 70 a footnote is added to 

 explain that " I gramme = the i, 000th part of a cubic 

 metre, about nine solid feet of water at the ordinary 

 average temperature." 



Under the head of " Operation of Light on the 

 Elements/' which commences on p. 107, we find that 

 chlorine is "a greenish strong-smelling gas developed 

 from chloride of lime," that bromine " is an unpleasantly 

 smelling substance of a fluid nature," and that iodine is 

 " a black substance also of a fluid nature and used for 

 friction." " Sulphur unites with oxygen and produces 

 the pungent strong-smelling sulphuric acid ; " " chloride 

 and bromide gas show a pecuhar relation to light even in 

 their combinations ; " and lastly, iodine again appears as 

 a "solid body appearing in the form of shining black 

 crystals, and emitting, when heated, a wonderful violet 

 vapour." 



Under the head of " Chemical Effects {of Light on 

 Salts of Silver," chloride of silver forms a " cheesy " pre- 

 cipitate ', chloride, bromide, and iodide of silver are " very 

 tenacious bodies ; " when chloride of silver is exposed to 

 light, the "chloride is liberated, and disappears as a 

 greenish gas, which, from its abundance as well as its 

 odour, can be perceived to be chloride of silver." " Green 

 vitriol is greatly attracted by oxygen, and taking it up 

 readily, passes into sulphate of iron." 



On p. 1 1 8 we have the following lucid description of the 

 toning process : — " The positive prints are subjected to a 

 further treatment styled the colouring process. To this 

 end it is plunged in a very diluted solution of gold. This 

 solute {sic) contains chloride of gold. Metal silver has 

 more affinity with chlorine than gold ; hence it combines 

 with the chlorine, forming chloride of silver, while the 

 gold is precipitated. It becomes separated in the shape 

 of a blue colour, adhering to the outlines of the picture, 

 and this blue, mixed with the brown of the picture, gives 

 a pleasant tone which does not change in the fixing-bath, 

 that is, in hyposulphite of soda." The latter body is, by 

 the way, alluded to indifferently as hyposulphite of soda, 

 " fixing sodium," and " fixing natrium." 



In photographic apparatus the translator is equally 

 at sea. A dark slide is continually spoken of as a 

 " cassette," and a printing frame as a " copper frame." 

 The technical names of the processes are also as a rule 

 incorrect. 



We have no patience to devote more time to this 

 wretched translation, which is only passable in portions 

 of the part on the physics of some of the photographic 

 processes. 



While Dr. Vogel is held to blame for a prolixity 

 and discursiveness which, together with the childishly 

 elementary character of much of the work, render it very 

 dull, the editors of the " International Scientific Series " 

 must be held responsible for still further reducing the 

 value of the work. by employing a translator ignorant of 

 the subject. 



R. J. F. 



OUR BOOK SHELF 

 Ornithological Miscellany. By George Dawson Rowley, 

 M.A., F.Z.S., Member of the British Ornithologists' 

 Union. Part I., No. I. January 1875. (London: 

 Triibner and Co.) 



The first number of Mr. Rowley's " Ornithological Mis- 

 cellany " is devoted to the illustration of some of the rarer 

 birds of New Zealand which have lately come into his col- 

 lection. The most interesting of these is perhaps the large 

 spotted Apteryx discovered by Mr. Potts in 1873, and 

 named after Dr. Haast, of which, we believe, Mr. Rowley's 

 specimens are the first that have reached this country. 

 Figures of and remarks on the other known species of 

 Kiwi are also given, so that we have altogether a nearly 

 complete account of what has yet been ascertained re- 

 specting the external form and habits of these singular 

 birds. Mr. Rowley passes on to discuss the structure of the 

 feathers of the Struthious birds, of which he also gives us 

 some admirable illustrations. A glance at these will serve to 

 show how very far removed in many essential points is 

 the genus Apteryx from the Cassowaries and others of 

 the order Struthiones, with which it is commonly asso- 

 ciated. Finally, Mr. Rowley gives us an account of a 

 white variety of one of the Nestor parrots of New Zea- 

 land, which, as all birds are subject to the occasional 

 influences that produce albinism, is not, perhaps, after all, 

 of special interest ; but Mr. Keuleman's well-drawn figure 

 of this bird will be appreciated by all ornithologists. 



Such are the contents of Mr. Rowley's first number. 

 In regretting that he does not know when the next will 

 appear, or what it will contain, we fully sympathise with 

 the author. But if Mr. Rowley can produce from his 

 cabinets a similar series of rarities to figure, and find an 

 equally good artist to draw them, we are sure that his 

 second and following numbers will meet with equal appre- 

 ciation from every lover of natural history. 



On Numerals in Americatt Indian Languages, and the 

 hidian Mode of Counting. By J. Hammond Trum- 

 bull, LL.D. (Hartford, Connecticut, 1875.) 



From a careful examination of the numerals in various 

 North American languages, Dr. Trumbull adds some 

 interesting evidence to that already available as to the 

 native development of arithmetic among uncultured races. 

 The derivation of numeral-words from the names of the 

 fingers habitually used in counting numbers is well shown 

 in Hudson's Bay; Esquimaux eerkitkoka = "little finger" 

 being used as a numeral for 10, while mikkeelukkamoot — 

 " fourth finger " signifies 9. Other materialistic sources 

 of numeral-words are apparent in the Micmac language, 

 where tabu = " equal " has become a numeral for 2 (like 

 our own word "pair," from Latin par), while tchicht, 

 which means 3, may have originally meant " more " or 

 "again," and been used to distinguish the plural as 

 beyond the mere dual (compare Latin trans and tres). 

 As in the civilised Old World languages with which 

 philologists especially occupy themselves, the numerals 

 have for the most part lost the traces of their original 

 significance, their development, a not unimportant part 

 of the intellectual development of mankind, has to be 

 learnt from investigations like the present into savage or 

 barbarian tongues. E. B. T. 



LETTERS TO THE EDITOR 

 [The Editor does not hold himself responsible Jor 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. '\ 



British Rainfall, 1874 



I AM much obliged by your favourable mention (Nature, vol. 



xii. p. 76) of my annual volume, and am very glad to find that it 



concludes with a suggestion, because, to quote from p. 138 of 



