the rock, the only possible explanation other than that the structures are due to secondary "concretionary" changes in the sedimentary mass, is that we have here structures that might be compared to stromatolites and oolites-primary deposits, yet not of a character that would justify the introducing of generic and specific names. Yet there are fundamental differences between oolites and the specimens shown in figures 1 and 3, and between stromatolites and specimens like those in figures 2, 5, and 6. First among these differences is the great thickness of the lamina when compared to the delicate laminations of oolites and stromatolites (the corresponding hot-spring and "sinter" calcareous deposits included); another is the very considerable dimensions of the spherical bodies here shown, a parallel to which is not known from recent deposits. In addition, we see that the spherical bodies often pass with their lamination into each other, as may very distinctly be seen in parts of the specimen depicted in figure 3, and even more so on the other side of the specimen. The spheres are parts of a large coherent mass. This feature contrasts decidedly with the ordinary oolitic structure, but is not infrequently seen in typical concretions, e. g., in chert nodules where the lamina may be arranged around different centers, yet the outer laminæ of one sphere pass into the corresponding ones of the neighboring spheres. In the botryoidal concretions so common in the Fulwell quarries, we have great clusters of coherent spheres that suggest a somewhat similar mode of formation. A most important feature of difference is the existence of a sometimes extremely strongly marked radiating element in the Permian structures; a similar type of radiating rods is not known in stromatolites and oolites. When there is a radiating structure in oolites, it is due to crystal fibres, while the rods of the structures here figured are made up of fine-grained-sometimes extremely fine-grained-limestone. We may have tube-like structures in the stromatolites, indeed these are very typical, but these tubes are, when the rock is in an unchanged condition, not at all of a similar regular type.11 Thus, judging from the general characters of the speci How a secondary chemical change of the rocks tends toward giving a more regular, geometrically arranged pattern is illustrated in the regularity of the silicified tubes in the stromatolite layer from the Alten district figured in my article on Finmarken of 1919 (p. 93), when compared with the figure on page 91 of the same paper whch shows the typical irregularly tubular stromatolite structure of an unaltered dolomite. mens illustrated in this paper, we are brought to think of all these structures, as do the English geologists, as being formed secondarily by very important radical internal changes in the rocks. It has also been pointed out by several of these investigators-and I wish to emphasize this fact-that some of the characters of these structures suggest those developed by crystallization processes. Abbott (1900) points out the likeness of the "lines" and "planes" in the concretionary beds to the "lines which shoot across congealing water." I might mention especially that the regular right-angle relation between the direction of the concentric and vertical element of the structures seems to be of a similar character to the right-angle relation so commonly seen between the direction of the crystal fibres and the concentric laminæ in a laminated crystalline rock, taking as an example a piece of laminated, fibrous, crystalline aragonite like the one the structure of which is indicated in the lower drawing of figure 8, or the well known radiating fibres of calcite (or pyrite which by metasomatic change has taken the place of calcite) in an ordinary lime concretion. That the changes in these rocks in general have been great can not well be doubted, and this fact is certainly proved by the English investigators. Yet it is in the residual material of a rock with a cellular structure similar to that which is so common in the Durham limestone that the extremely delicate chains of cells representing parts of blue-green alga were observed. In sections of specimens of Gallatinia pertexta, a "species" which, as emphasized also by Walcott, is certainly very septaria-like, are reported minute remains of bacteria. This fact may not seem to harmonize very well with the idea of great internal changes in the rock, but we have only to consider how very delicate structures are often preserved in concretions of lime or of silica, where a transportation of mineral matter has also taken place, to realize that the secondary character of the rock and the occurrence of minute cells of plants are not mutually exclusive phenomena. The discovery of algae and bacteria in pre-Cambrian strata, reported by Walcott, has therefore lost none of its importance, even if it should be found that these organisms are not responsible for the many curious structures found in the Algonkian Newland limestone. University, Kristiania, October, 1920. SCIENTIFIC INTELLIGENCE. I. CHEMISTRY AND PHYSICS, 1. Perchloric Acid as a Dehydrating Agent in the Determination of Silica.-H. H. WILLARD and W. E. COKE, of the University of Michigan, have found that the use of perchloric acid gives marked advantages over the usual methods for this very frequently required analytical determination. The dihydrate of perchloric acid, HCIO,.2H,O, boils at 203°C, and at this temperature is a powerful dehydrating agent. Nearly all its salts are soluble in the strong acid and in water, presenting in this respect a great advantage over sulphuric acid for this purpose. The pure acid has been on the market for some time, and although still rather expensive it could be made more cheaply if there were sufficient demand for it. The method as applied consists in dissolving the metal or silicate in hydrochloric or nitric acid, adding perchloric acid, or dissolving directly in perchloric acid, evaporating to dense fumes of the latter, boiling gently, in a covered beaker to avoid undue waste of the acid, for 15 or 20 minutes to dehydrate the silica, cooling and diluting with water. All salts are instantly soluble and the silica is filtered off and determined as usual. It contains less impurity than when separated by the usual methods. Moreover the silica remaining in solution is much less than in the usual method of evaporation to dryness and treatment with hydrochloric acid, so that except for the most accurate work it can be neglected. The operation is simple and rapid. Test analyses made by the authors upon very pure quartz sand (after fusion with sodium carbonate), upon cements, limestones, samples of willemite, irons, steels, aluminium and nickel gave very good results. It seems probable that this new method will find extensive application, both in scientific and technical analysis. Jour. Amer. Chem. Soc., 42, 2208. H. L. W. 2. The Chemistry and Crystallography of Some Fluorides of Cobalt, Nickel, Manganese and Copper.-It is sometimes desirable, perhaps, to call attention to a chemical article for the purpose of showing that it is unsatisfactorily presented. Such appears to be the case in this article by FLOYD H. EDMISTER and HERMON C. COOPER, which takes up about 15 pages of an important chemical journal. They have described the acid fluorides CoF..5HF.6H,O, and CuF.5HF.6H.O. Upon reading this article one would suppose that these compounds were new ones, and of a new type. The authors refer to some work by Böhm in 1905 upon acid fluorides of cobalt, nickel and copper, and say, "The formulas assigned by Böhm to these fluorides are of a strongly acid type." Nothing further is said about Böhm's formulas, but upon consulting Böhm's article it appears that he described, besides others, the salts CuF2.5HF.5H2O, and CoF.5HF.6H2O, two of which are identical with those of Edmister and Cooper, while the other one varies by only a single molecule of water. Böhm described also the crystalline form of all of these salts. There is no doubt that Edmister and Cooper should have mentioned Böhm's results.-Jour. Amer. Chem. Soc., 42, 2419. H. L. W. 3. Notes on Chemical Research, by W. P. DREAPER. 12mo, pp. 195. Philadelphia, 1920 (P. Blakiston's Son & Co.).-This book from England now appears in a considerably enlarged second edition. It gives a general discussion of chemical investigations, and is intended particularly for the use of young chemists who are engaged or about to be engaged in industrial work. The book is an interesting one and it gives much useful information and advice. Many will not agree with the opinion of the author that a post-graduate course of research work in college is of doubtful advantage to the industrial research chemist, but very probably this opinion is the correct one in connection with most of the chemical manufactures in England. The view is expressed that it is seldom that a man can combine the experience and qualifications of a first-class chemist and of an engineer; hence the combination of the two professions in the "so-called chemical engineer" is not approved of. H. L. W. 4. Elementary Chemistry for Coal-mining Students; by L. T. O'SHEA. 12mo, pp. 319. London, 1920 (Longmans, Green and Co. Price, New York, $3).-This book has been prepared for the use of a special class of students, for whom the ordinary text book of chemistry is not well adapted, since it contains. much that is unnecessary for them to study, and since much that it is desirable for them to know is not found in it. It appears that the book is a very satisfactory one for its purpose. It presents clearly the fundamental principles of the science, it discusses particularly the elements occurring in coal, while special attention is paid to the explosive, suffocating and poisonous gases that may occur in coal mines. The chemistry and technology of coal and coke and the by-products are well presented, while the discussions of explosives and explosions of gases and coal dust are particularly good. On account of its excellent special features the book should be of interest to many who are not directly connected with coal mining. H. L. W. 5. Creative Chemistry, by EDWIN E. SLOSSON. 12mo, pp. 311. New York, 1920 (The Century Co.).-This book gives an account of recent achievements in the chemical industries in a popular and very forcible style. The subjects treated include explosives, artificial fertilizers, coal-tar colors, synthetic perfumes and flavors, cellulose, synthetic plastics, rubber, sugar, corn products, fats and oils, fumes for warfare, electric furnace products, and metals and alloys. There are many excellent illustrations, and an extensive list of references for reading is appended. The book is an excellent one for the general reader, and it appears to be well adapted to arouse the interest and increase the knowledge of chemical students. H. L. W. 6. The Thermionic Vacuum Tube; by H. J. VAN DER BIJL. Pp. xix, 391. New York 1920 (McGraw-Hill Book Co.).—No physical discovery or development of the last decade can compare in importance with the vacuum tube, which certainly ranks with the telephone, and possibly with the dynamo in its value to our social economy. It is the fruitage of the patient labors of two generations of scientists, and the principles of its operation cannot be comprehended in any engineering rule of thumb. The student who seeks to master its operation will have need of a thorough preparation in physics and mathematies. The use of the vacuum tube was greatly stimulated by the war and while much that was then discovered has possibly not yet been released, the present treatise is easily the foremost presentation of its theory and applications which has yet. appeared. Chapters I, II, III, and V treat of the nature of electrons, their release from bodies and the phenomena of ionization. Chapter IV details the characteristics of various tubes, a technical term meaning the functional relation between the variables of the tube. Chapter VI explains the use of the tube as a "valve" or rectifier. Chapter VII treats the three electrode tube or audion as amplifier. Chapter VIII is devoted to the tube as generator of electric oscillations. Chapter IX explains the modulation and detection of currents, and Chapter X discusses the function of the tube in a variety of other applications. This exposition of the author carries especial weight because he occupied for some time the position of research physicist with the American Telephone and Telegraph Company and with The Western Electric Company. F. E. B. 7. Où en est La Météorologie; by ALPHONSE BERGET. Pp. vii, 300. Paris, 1920 (Gauthier-Villars et Cie).-This is one of a series of a dozen or more projected volumes (Collection des Mises au Point), aiming to give a compendious presentation of AM. JOUR. SCI.-FIFTH SERIES, VOL. I, No. 2.-FEBRUARY, 1921. |