A tholeiitic andesite flow unit among the Causeway Basalts of North Antrim in Northern Ireland

A tholeiitic andesite flow unit occurs in tholeiitic basalt lava in the Giant's Causeway region of North Antrim, Northern Ireland. It is the first example of an intermediate differentiate to be found among these quartz-normative basalts. Separate magma batches for the preceding and succeeding basalt formations are indicated by their Zr/P2O5 ratios, and by the differing fractionation trends shown by molecular proportion ratio plots. The tholeiitic andesite was probably extruded in a superheated condition with few crystal nuclei, and subsequent undercooling produced an unusual fasciculate/spherulitic texture in contrast to the very fine and even grain of the host basalt. A liquid–liquid interface between the flow units shows small-scale lava mixing.

CONSTITUTION OF AN ARABINOGALACTOMANNAN FROM HONEY

An arabinogalactomannan isolated from honey consisted of D-mannose, L-arabinose, and D-galactose in molar proportions of 1.0:2.04:4.04 respectively. Electrophoretic and sedimentation results indicated that the arabinogalactomannan was homogeneous. Methylation studies showed a highly branched structure. Hydrolysis of the methylated polysaccharide gave 2,3,4,6-tetra-O-methyl-D-mannose (3 molecular proportions); 2,3,4,6-tetra-O-methyl-D-galactose (2 molecular proportions); 2,3,5-tri-O-methyl-L-arabinose (1 molecular proportion); 2,3,4-tri-O-methyl-D-galactose (6 molecular proportions); 2,3-di-O-methyl-L-arabinose (4 molecular proportions); 2,5-di-O-methyl-L-arabinose (1 molecular proportion); 2,4-di-O-methyl-D-galactose (5 molecular proportions). The general structural features of the arabinogalactomannan are discussed.

STRUCTURE OF THE EXTRACELLULAR POLYSACCHARIDE PRODUCED BY XANTHOMONAS ORYZAE

The extracellular polysaccharide isolated from cultures of Xanthomonas oryzae is composed of D-glucose (5 molecular proportions), D-glucuronic acid (2 molecular proportions), and D-mannose (5 molecular proportions). Acid hydrolysis of this polysaccharide, which contains 0.3% combined pyruvic acid, yields 2-O-β-D-glucopyranosyluronic acid D-mannose, which has been characterized as its crystalline fully methylated β-glycoside. Hydrolysis of the methylated polysaccharide gives 2,3,4,6-tetra-O-methyl-D-mannose (3 molecular proportions), 2,3,4-tri-O-methyl-D-glucuronic acid (1 molecular proportion), 2,3,6-tri-O-methyl-D-glucose (4 molecular proportions), 3,4,6-tri-O-methyl-D-mannose (2 molecular proportions), 2,6-di-O-methyl-D-glucose (3 molecular proportions), 2,3-di-O-methyl-D-glucose (1 molecular proportion). The polyalcohol derived from the polysaccharide by periodate oxidation followed by sodium borohydride reduction gives upon acid hydrolysis glycerol (2 molecular proportions), erythritol (1 molecular proportion), and D-glucose (1 molecular proportion). The general structural significance of these findings is discussed.

The Action of Hypochlorous Acid on Rubber

It has been previously observed that when rubber latex is treated with cold aqueous hypochlorous acid, the simple additive attachment of the hypochlorous acid molecule at the ethylenic center of each C5H8 unit of the rubber molecule may be accompanied by a considerable amount of substitutional chlorination (cf. preceding article). An analogous behavior has now been found to characterize the interaction of dissolved rubber (rubber solutions) with hypochlorous acid, but in this case marked differences in the properties of the reaction products become manifest. In the treatment of dissolved rubber some evidence of substitutional chlorination is directly apparent, even where the amount of hypochlorous acid does not exceed one molecular proportion per C5H8 unit, and considerable replacement of hydrogen by chlorine occurs when the reagent is present in excess of this amount; indeed, by using a suitable excess of the latter, it is possible to obtain chlorinated materials with a maximum chlorine content of 66 per cent. Now it is of practical importance to note that, whereas the chlorinated materials obtained from latex are characterized by a high degree of insolubility, the analogous materials from dissolved rubber are relatively soluble, and in the case of some of the more highly chlorinated materials are readily soluble in the ordinary solvents for rubber.

An examination of the physical and physiological properties of tetrachlorethane and trichlorethylene

Introductory :- Within the last few years chloroderivatives of the aliphatic hydrocarbons, other than the familiar chloroform, have been used for various purposes, occasionally with fatal results. It would, therefore, appear desirable to apply physiological tests, in the first instance, to such compounds to ascertain whether they might reasonably be scheduled as poisons, before they are entrusted to the hands of unskilled and ignorant persons. As two such substances, namely (1) one of the isomeric tetrachlorethanes, and (2) trichlorethylene, came into my hands through Dr. Willcox, they were compared with chloroform (taken as a standard) by the muscle method; further, as the physical data at least of the latter compound have been curiously overlooked, the opportunity was taken of determining certain of these by instruments, calibrated for previous investigations. Historical .-Symmetrical tetrachlorethane, sometimes called acetylene perchloride, CHCl 2 . CHCl 2 , was first obtained by Berthelot and Jungfleisch from acetylene and chlorine gases in presence of antimony chloride; the substance is described as a liquid, b. p. 147, soluble in alcohol, insoluble in water. These writers also showed that when this compound is heated with alcohlic potash, one molecular proportion of hydrochloric acid is removed with formation of trichlorethylene, CHCl : CCl 2 , a liquid, b. p. 88, of chloroform-like odour.