722 



SCIENCE 



[N. S. Vol. XLIII. No. 1116 



Th-e Petrology of Some South Sea Islands and its 



Significance : Joseph P. Iddings. 



The islands of Tahiti, Moorea, Huaheine, Eaia- 

 tea, Tahaa, Bora Bora of the Society group, and 

 Hiva-oa and Nukahiva of the Marquesas were vis- 

 ited in order to ascertain whether the volcanic 

 rocks composing them are of such a character that 

 they support the theory of isostasy, which demands 

 that the deep portions of the earth's crust, or the 

 lithosphere, under the Pacific Ocean should consist 

 of heavier material than that underlying the con- 

 tinent of North America. It was found that the 

 volcanic rocks of these islands are noticeably heav- 

 ier on the average than the igneous rocks occur- 

 ring in various parts of the American continent. 

 Each of the islands visited was found to be an 

 extinct basaltic volcano, considerably erodedj and 

 partly submerged beneath the sea. The structure 

 and rocks of the islands are briefly described and 

 characteristic views are shown by means of lan- 

 tern slides. 



Coal Formation: J. J. Stevenson. 



The doctrine that the fossil fuels from peat to 

 anthracite are a continuous series has been subject 

 of renewed discussion within recent years. The 

 writer felt compelled to make serious investigation 

 to free himself from doubts aroused by the state- 

 ments of some authors. The study proved unex- 

 pectedly difficult, for the disputants have very 

 little common ground and one can hardly deter- 

 mine what kind of evidence may be acceptable to 

 all. Some collateral matters, of much importance, 

 have been overlooked and little information exists 

 respecting them. These are chiefly chemical and 

 the studies require extensive equipment as well as 

 expenditure of much time, neither of which is at 

 the writer's disposal. But assurances have been 

 received from the presidents of several great or- 

 ganizations that the investigations will be made 

 and that the results will be in readiness for the 

 final summary. The general study has advanced 

 so far, in the writer 's opinion, as to justify pres- 

 entation of the first part of his monograph. The 

 plan adopted is to discuss the fuels in order of age, 

 beginning with peat and closing with the Paleozoic 

 coals. The first part considers peat and the Ter- 

 tiary coals; the second will consider the Mesozoic 

 and the Paleozoic coals. The writer hopes to make 

 evident the inherent probability of the doctrine 

 that, in spite of difl'erence in plant materials, the 

 coals throughout form a connected series, not 

 merely in mode of accumulation, but also in phys- 

 ical structure and in chemical composition. 



California LaTces and the Solar Hypothesis of Cli- 



matio Changes: Ellsvs'Orth Huntington. 

 Color Photographs of the Phosphorescence of Cer- 

 tain Sulphides: Edwaed I. Nichols. 

 iBy the use of a new form of phosphorescope the 

 author has succeeded in taking photographs by the 

 Lumi6re process, which shows the colors of certain 

 phosphorescent sulphides of the Lenard and Klatt 

 series. The change of tint by decay and the strik- 

 ing changes of color produced by cooling to the 

 temperature of liquid air are exhibited by means 

 of these photographs and the theory is very briefly 

 discussed. 



miDAT, APRIL 14 



Afternoon Session — 2 o'clooh 

 William B. Scottj Sc.D., LL.D., Vice-president, in 



the Chair 

 A New and very Sensitive Indicator for Acidimetry 



and AlJcalimetry and for Determining Hydrogen 



Ion Concentrations between the Limits of 6 



and S on the Sorensen Scale: G-. Scatchaed and 



Maeston T. Bogert. 



The authors have discovered that dinitro benzo- 

 ylene urea (dinitro 2-, 4-diketotetrahydroquinazo- 

 line^ dinitro 2-, 4-dihydroxyquinazoline) is an 

 unusually sensitive indicator and one which can be 

 prepared easily, in any desired amount, from an- 

 thranilic acid. It changes from colorless to green- 

 ish yellow with a change in hydrogen ion concen- 

 tration from 10"° to 10"', the development of the 

 coloring following regularly the decreasing concen- 

 tration of hydrogen ion. It is very little affected 

 by neutral salts or proteins, and not at all by the 

 ordinary biological preservatives, chloroform and 

 toluene. The color does not fade perceptibly in 

 two days, and but very slightly in a week. It 

 therefore promises to be very useful in the meas- 

 urement of hydrogen ion concentration of biolog- 

 ical or other liquids in this important range, for 

 which the previously known indicators are not 

 very satisfactory. It is possible with it to detect 

 the eflEect of one drop of N/100 NaOH in 100 c.c. 

 of solution, and titrations of N/100 HCL with 

 N/100 NaOH checked within O.L per cent. Under 

 similar conditions -nitrophenol required 5 to 6 

 drops, and methyl orange 10 to 12 drops, to give a 

 sure end-point. Its chief objection is its yellow 

 color, which renders it unsuitable for determina- 

 tions in artificial light. 

 Bacterio-chemical Studies of Decay of the Teeth: 



William J. Gies. 

 The Human Gastric Secretion: Martin E. Eeh- 



FDSS. (Introduced by Dr. Philip B. Hawk.) 



