188 Bibliography. 



obtained from it ; when moist, it yields a large quantity ; when dry, 

 very little. Dr. Jackson considers the 10 per cent, of water, as wa- 

 ter of composition ; but we have found that this coal, after lying a 

 long time in a hot and dry garret, afforded very little gas at ignition, 

 but gave abundance when moistened. The author is of the opinion 

 that this coal will answer well for furnaces but not for parlor grates, 

 as the ashes will form slag ; but he does not donbt that the mines 

 may be profitably wrought, and that the coal exists in sufficient quan- 

 titiy to justify thorough working of the mines. He has given very 

 valuable comparative statements respecting the properties of the va- 

 rious anthracites of our country, and has described particularly the 

 mines of Mansfield, in Massachusetts, which are in the same geolo- 

 gical formation, but our space does not permit us to quote these valu- 

 able remarks. We trust the time is not distant when the mines of 

 Rhode Island and of Mansfield will be again explored, and with de- 

 cisive advantage. 



Block Island, twenty five miles from Newport, and fifteen from 

 Point Judith, is a very small territory with tertiary surface of granitic 

 origin, and presents little that is interesting in geology beyond nume- 

 rous peat beds, bog-iron ore, clays, sand and bowlders : the latter are 

 of granite, and are identical with those on Point Judith and at Kings- 

 ton, on the continent, while they rest on a substratum of blue clay, 

 upon which they must have been deposited by diluvial causes — water 

 and ice, aided by winds and currents. There are no shells in the clays 

 of this island, which sometimes form cliffs of seventy to one hundred 

 feet perpendicular, while the hills rarely exceed one hundred and fifty 

 feet above the sea level. There is no harbor — the boats are drawn 

 on shore by oxen when a storm is at hand ; the sea washes away the 

 land in some places, and the best defense is the long line of bowlders 

 which fortify the coast, and repel the buffeting of the waves ; to re- 

 move them would therefore be very injudicious. 



This island, with fifteen hundred industrious inhabitants, is fairly 

 entitled to a breakwater, or artificial harbor, to be erected at the ex- 

 pense of the general government. 



2. Some notice of the Agricultural part of Dr. Jaclisoii's Report. 

 This report is characterized by the extent of its agricultural obser- 

 vations, and by the great number and accuracy of chemical analyses 

 of soils, peats, limestones, and other substances of interest to the 

 practical agriculturalist. Nearly two hundred of these analyses are 

 given, which have been performed chiefly on the soils, &c. from Rhode 

 Island. Dr. Jackson has not however in this report confined his re- 

 searches exclusively to that state, but has sought for facts and infor- 

 mation from the practical farmers of Massachusetts, and examined 

 soils from various and widely different parts of the world, whenever 



