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Resins in paleozoic plants and in coals of high rank
482
CURRENT TOPICS.
[j. iv. I.
Resins in Paleozoic Plants and in Coals of High Rank. D. WHITE. (U. S. Geol. Survey, Paper 85 E, 65.)--The supposed absence of resins from the coals of higher rank has led to the view that the coal-forming floras of the Carboniferous period, to which most bituminous and higher-rank coals belong, were destitute of resinbearing plants, and that these coals have not at any time existed as peats. From a study of petrified fragments of Carboniferous plants, and from observations of Paleozoic coals (" stone-coals "), the author concludes that some of the Carboniferous coal-forming vegetation contained secretions of a resinous nature which became concentrated in the coals, owing to dehydration and the more rapid decay of the other plant tissues. Lump or exudate resins, as well as canal secretions, were found in Paleozoic coals of low bituminous rank. The failure to detect their presence in coals of higher rank is considered to be due to the changes which the resins undergo during the transformation of the coal. These changes, as shown in the coals of the Cretaceous and Tertiary periods (usually lignites or brown coals), are a darkening of the color to a smoky brown, followed by blackening, cracking, and shrinking of the lumps, which are later reduced to dark brownish-black, spongy or granular residues and finally to a fine, thin, powdery black scale. The reduction of the resins coincides with rapid deoxygenation of the coal, and occurs when the proportion of fixed carbon in the coal substance is "6o to 65 per cent. The qualities essential to the production o~ highgrade coke are developed at the same time. The Paraffin Motor. ANON. (Times Eng. Suppl., x, 48.)-Paraffin motors are suitable for powers of from 20 to IOO horsepower and have been constructed up to 18o horse-power. The power obtained is about IO per cent. less than with petrol, and the consumption is 0.7 to 0.8 pint of paraffin (specific gravity 0.82) per British horse-power hour. The normal speed varies from 5oo to 8oo revolutions per minute with the size of the motor, and the motor can be run down to one-fourth the normal speed. Paraffin carburettors, for running a petrol engine with paraffin, are not entirely satisfactory. In the paraffin motor the vaporizer is usually heated by the exhaust gases, and the engine is started on petrol, or the vaporizer is heated up by a blast lamp. A lower compression is used than in petrol motors. Prevention of Corrosion of Iron and Steel. (Brit. Pat. H,966 of I913.)--The objects are heated up to about 75o° C. and subjected
to the action of a rapid stream of dry ammonia gas for about an hour and a half, after which the furnace is allowed to cool slowly and the current of gas slackened off. By this means a protective layer of iron nitride, Fe2N, is formed. The nitrified iron is stated to be proof against atmospheric oxidation. The patentee is H. Hanemann.
CURRENT TOPICS.
[j. iv. I.
Resins in Paleozoic Plants and in Coals of High Rank. D. WHITE. (U. S. Geol. Survey, Paper 85 E, 65.)--The supposed absence of resins from the coals of higher rank has led to the view that the coal-forming floras of the Carboniferous period, to which most bituminous and higher-rank coals belong, were destitute of resinbearing plants, and that these coals have not at any time existed as peats. From a study of petrified fragments of Carboniferous plants, and from observations of Paleozoic coals (" stone-coals "), the author concludes that some of the Carboniferous coal-forming vegetation contained secretions of a resinous nature which became concentrated in the coals, owing to dehydration and the more rapid decay of the other plant tissues. Lump or exudate resins, as well as canal secretions, were found in Paleozoic coals of low bituminous rank. The failure to detect their presence in coals of higher rank is considered to be due to the changes which the resins undergo during the transformation of the coal. These changes, as shown in the coals of the Cretaceous and Tertiary periods (usually lignites or brown coals), are a darkening of the color to a smoky brown, followed by blackening, cracking, and shrinking of the lumps, which are later reduced to dark brownish-black, spongy or granular residues and finally to a fine, thin, powdery black scale. The reduction of the resins coincides with rapid deoxygenation of the coal, and occurs when the proportion of fixed carbon in the coal substance is "6o to 65 per cent. The qualities essential to the production o~ highgrade coke are developed at the same time. The Paraffin Motor. ANON. (Times Eng. Suppl., x, 48.)-Paraffin motors are suitable for powers of from 20 to IOO horsepower and have been constructed up to 18o horse-power. The power obtained is about IO per cent. less than with petrol, and the consumption is 0.7 to 0.8 pint of paraffin (specific gravity 0.82) per British horse-power hour. The normal speed varies from 5oo to 8oo revolutions per minute with the size of the motor, and the motor can be run down to one-fourth the normal speed. Paraffin carburettors, for running a petrol engine with paraffin, are not entirely satisfactory. In the paraffin motor the vaporizer is usually heated by the exhaust gases, and the engine is started on petrol, or the vaporizer is heated up by a blast lamp. A lower compression is used than in petrol motors. Prevention of Corrosion of Iron and Steel. (Brit. Pat. H,966 of I913.)--The objects are heated up to about 75o° C. and subjected
to the action of a rapid stream of dry ammonia gas for about an hour and a half, after which the furnace is allowed to cool slowly and the current of gas slackened off. By this means a protective layer of iron nitride, Fe2N, is formed. The nitrified iron is stated to be proof against atmospheric oxidation. The patentee is H. Hanemann.