192 



NA TURE 



\_Dcx. 30, 18S0 



ought to be. In describing the tests for barium it is said 

 that the bead "can be flamed," but no explanation is 

 given of the process of flaming. The capital test for 

 bismuth with potassium iodide and sulphur is entirely 

 ignored. 



I now come to the third part, which treats of quanti- 

 tative assays. Mr. Attwood's plan of making a check 

 assay in every case with a small quantity of the pure 

 metal is certainly calculated to give the operator con- 

 fidence in his results. The author adopts i\ grain as the 

 amount of ore to be taken for an assay. I think he would 

 have done better to have followed Plattner and used the 

 French weights, because there is less chance of making 

 errors where each milligramme means i per cent. 



For the silver assay Mr. Attwood employs pieces of 

 ordinary charcoal instead of the far more convenient and 

 portable charcoal crucibles designed by Plattner. He also 

 describes a crucible assay for silver ores, which does not 

 appear to possess any advantage over Plattner's scorifica- 

 tion method. 



There is one most unfortunate error in the book to 

 which I feci bound to call .attention. Mr. Attwood 

 gives some tables for calculating the number of ounces 

 of gold or silver per ton from the results of assays of \\ 

 grain of the ore. In an unlucky moment he forgot that 

 gold and silver are weighed by troy weight, and calculated 

 his tables for avoirdupois ounces. The consequence is 

 that these tables are not only valueless, but also highly 

 misleading. Let us take one case as an example. Suppose 

 that li grain of ore had yielded o'oi grain of fine metal. 

 We look down the table (p. 117), and find, according to 

 Mr. AttvTOod, that the yield would be 23893 02. per ton ; 

 in reality the yield should be 21777 oz. 



Some neat little retorts have been designed by the 

 author for distilling ores of mercury and amalgam, but he 

 does not mention Kiistel's assay. 



On coming to the tin assay we have the peculiar state- 

 ment that silica may be separated from tin ore by boilin^f 

 t with hydrochloric acid. " The assay being finely 

 powdered, the silica is dissolved." " The dissolved silica 

 is decanted off" (p. 158). Cornish mine agents will be 

 surprised when they are told that, in order to obtain 

 correct results, it is necessary to wash or van as much as 

 J lbs. of an ordinary tin ore (p. 159). 

 „ Under the head of nickel no mention is made of the 

 valuable ores from New Caledonia. 



Small mistakes are numerous. The size of a box 

 is said to be "twelve inches square" (p. 3); we note 

 also: "a most useful addenda" (p. 24); "chloride of 

 ammonia" (p. 33); "mangan/te" instead of manganate 

 (?• 53)> ^nd permanganate (p. 54). The term "raw iron" 

 is used frequently instead of " pig iron," and shows that 

 the author has copied Cornwall's translation blindly. 

 Coal, anthracite, and graphite are said to " volatilise " 

 when heated in the platinum spoon (p. 82). Sieves are 

 jiiade with 2000 holes per " linear " inch (pp. 100 and 

 337). In the description of cupellation (p. 106) we read : 

 "The lead parts with portions of its o.\ygen to the copper 

 and other base metals." 



In conclusion 1 think that the value of the book would 

 be increased if a list of errata el corrigenda were inserted, 

 correcting some of the errors which, I regret to say, 

 impair its general usefulness. C. Le Neve Foster 



OUR BOOK SHELF 



Ubcr die von de7i Trichoptcrcnlarz'en der Provin- Santa 

 Catharina verfertigen Cehiiuse. Von Dr. Fritz Miiller. 

 ArcMvos de Museu national. Vol. iii. pp. 99-134, and 

 209-214. Rio de Janeiro, 18S0. (Aus dem Portu- 

 gieischen ubersetzt von dem Bruder des Verfasscrs, Dr. 

 Hermann MiiUer in Lippstadt.) 

 Dr. Fritz Muller has for some years been engaged 

 upon an investigation of the habits of the Caddis-flies of 

 Santa Catharina, and has shown extraordinary skill in 

 breeding these insects, a matter always difficult, and 

 especially in the case of those that inhabit running water. 

 The results of his researches were foreshadowed in various 

 notes published in the Zoologischcr Anzeigcr and in the 

 Ti ansactions of the Entomological Society of London 

 for 1879. S"t it "was well known that the extended infor- 

 mation and figures would be given in the Rio de Janeiro 

 Archivos. As this publication is somewhat difficult to 

 obtain, and as most of us are not familiar with Portu- 

 guese, Dr. Hermann Miiller has conferred a great 

 boon by publishing a translation of the paper (accom- 

 panied by the two folded plates) in the Zcitschrift 

 fiir loissenschaftliche Zcologie for the present year 

 (pp. 47-87, plates iv. and v.). It is needless to state that 

 the details are of the greatest interest, and we have 

 here the most important contribution to the natural his- 

 tory of Triclwptera that has appeared since the publica- 

 tion of Pictet's " Recherches " on the species of Geneva, 

 and worked out in a far superior manner. We cannot 

 here even allude to most of the many marvels of insect- 

 architecture and habits that Dr. Fritz Muller has revealed. 

 Some of the most interesting are the numerous forms of 

 Hclicopsyche, which build little sand-cases so like shells 

 that they have been described as such ; those Dcntaliuin- 

 like cases, originally noticed by Aug. St. Hilaire as 

 Griimicha, which name our author retains ; those in- 

 stances of parasitism (or worse) in which a larva of one 

 species dispossesses that of another of its house and con- 

 verts it to its own purposes ; those very numerous forms 

 of Hydroptilido', the most minute of all Tric/ioptera,yi\\.\i 

 cases of the most varied and wonderful structure ; above 

 all, that most interesting fact that the rain-water which 

 collects at the bases of the leaves of some Broineliaca 

 has a special fauna of its own, including at least one 

 Caddis-worm. The descriptions of these and many 

 others will be read with delight by every biological stu- 

 dent ; and we hope Dr. Muller will follow up the paper 

 by records of further discoveries, for here, as in all his 

 works, the evidences of superior powers of observation 

 strike one on every page. 



The plates are excellent, and aid much in a realisation 

 of the descriptive portion. Dr. Midler's artistic powers 

 are so marked that wc cannot but regret he has not fur- 

 nished details of the form and structure of the perfect 

 insects also, which would have greatly aided systematists ; 

 in fact the perfect insects are only alluded to in a casual 

 manner. 



f 'oyages of the Elizabethan Seamen to Ameriea. Thirteen 

 Original Narratives from the Collection of Hakluyt, 

 Selected and Edited, with Historical Notices, by E. J. 

 Payne, M.A. (London : De La Rue and Co., 1880.) 

 We do not quite understand Mr. Payne's reason for 

 publishing this selection from Hakluyt's classical collec- 

 tion of voyages. The selection is, however, judicious, 

 and cannot fail to be interesting, and at the same time 

 instructive, to those who desire to become familiar with 

 the first beginnings of English conquest in America. 

 Mr. Payne's famiUarity with the subject of British coloni- 

 sation, as exemplified in his excellent little "History of 

 European Colonies," specially qualifies him for making 

 such a selection as the present. His brief Historical 

 Introduction enables the reader to understand the special 

 significance of the voyages contained in this volume. He 



