Jan. 13, 1876] 



NATURE 



215 



range, which consists of two sub-ranges wholly of crumbled strata. 

 The average angles of dip are from 65° to 70^. The following 

 estimates are made : — The folded strata are of 2\ to 3 times the 

 length of a horizontal line drawn beneath them ; i.e. 15 to 18 

 miles of sea bottom have been crushed into 6 miles, the surplus 

 swelling upward. Numerous flattened clay pellets, chiefly ellip- 

 soids or disks, and similarly flattened nodules of sandstone, fur- 

 nished means of estimating the horizontal and vertical pressures 

 to which the mass has been subjected. The mathematical formula 

 employed was detailed. It was found that 2^ to 3 parts had 

 been crushed into one horizontally, and every foot of vertical 

 thickness had been thereby swelled up i\ or 3 feet. 



Major J. W. Powell of Washington has spent many years in 

 scientific exploration of the canons of Colorado latterly under 

 the auspices of the Smithsonian Institution. He regards the 

 geology of the Colorado region as so different from any other, that 

 a new system will have to be devised to meet it. RIajor Powell 

 offered the outlines of a new system for the details of this region, 

 proposing to retain as far as possible the names that mark the 

 labours of previous explorers in the field ; and to give in addition 

 geographical names as a provision expedient till the lull order 

 of the strata should be determined. The plateau region drained 

 by the Colorado River of the West was more particularly under 

 review in the essay before the Academy. Springing from the 

 plateaus are single mountains, short ranges, and volcanic cones 

 disposed in groups j the affluents of the river have their source in 

 high mountains on the edge of the drainage basin. The river 

 and its chief tributaries differ from other great rivers in the ab- 

 sence of considerable valleys along their course, at least north 

 of 35^^ latitude. The streams run in deep caiions, and these, with 

 other topographic features, separate the plateaus. This is part 

 of the whole region of the United States west of the looth meri- 

 dian, which is distinguished by being everywhere of great altitude, 

 with the trifling exceptions of a strip on the Pacific coast and 

 some valleys of the larger streams. The rivers descend so 

 rapidly that they are of little service for navigation ; the valleys 

 are exceedmgly narrow ; the table-lands and mountains are tree- 

 less, arid, and almost desolate. Bare rocks rarely masked by any 

 soil give character to the "Rocky Mountain" region. Here 

 there is everj'where an open book to the geologist, as the forma- 

 tions can be clearly traced, and the sections given by canons 

 display in regular succession the strata of palaeozoic, mesozoic, 

 and cainozoic eras, a total depth of 6o,cxx> feet being thus re- 

 vealed. The characteristics of the formations of this region were 

 discussed at considerable length. As an instance of the irregu- 

 larities of strata, the observations on lignite may be cited. 

 It is frequently found through a horizon of 11,500 feet, in beds 

 of varying thickness, distributed all the way from the lower 

 Cretaceous up through three divisions of the Tertiary ; but no 

 particular bed of lignite is persistent over a large area. In one 

 instance — the Rock Springs group — eleven beds of lignite were 

 found, varying from 10 inches to 4 feet in thickness ; but three 

 miles away, careful observation showed all these beds represented 

 by carbonaceous shales. In places separated by only a dis- 

 tance of a few miles, the succession of lignites is found to differ 

 materially ; they appear in general to have been formed in small 

 irregular basins. 



One of the most interesting papers read at the meeting was 

 that of Prof. Raphael Pumpelly, of Newburgh, N.Y., on the 

 Influence of Marine Life and Currents on the formation of Metal- 

 liferous Deposits. Beginning with the list of chemical elements 

 which are found in the sea — now numbering 29 and likely to be 

 largely increased — the author gave disinctive particulars as to the 

 proportions of these substances, and the material in which they 

 are found, whetlier sea-water, marine organisms, or structures 

 that are products of marine life. All elements which compose 

 the land are ultimately carried to the sea. The cycles through 

 which different substances pass in their progress from land to 

 sea, and thence again to the material of land, were traced in the 

 cases of carbonic acid, lime, phosphoric acid, fluorine, and 

 sulphur. As to the first of these, the sea is charged with nine 

 per cent, of COj, the charge varying with the surface condition 

 of the water and the immediate atmospheric conditions. The 

 activity of the wave surface aids the escape oi surplus carbonic 

 acid into the air. Plant life in the sea as on land effects the 

 decomposition of CO2, using the carbon to build vegetable 

 structure and freeing the oxygen to sustain marine vegetable 

 life. But the carbon that is withdrawn to form coal, owing to 

 its insoluble character, has been practically abstracted from this 

 circulation. The ultimate result, the author thinks, would have 

 been the decay of all life on the planet, for the want of the 



carbon thus locked up. Hence the work of man in mining and 

 burning coal restores the balance of this circulation, by bringing 

 the carbon into a condition in which it can be dissolved by 

 moisture and enter into plant life through the leaves. 



In describing the cycle of lime, Mohr's theory was alluded to. 

 Sulphate of lime, decomposed by plants, supplies sulphur to- 

 wards forming albumen by combining with cartwn and ammonia, 

 the oxygen being set ^ree ; carbonate of lime may perform a 

 simpler operation in the plant, leaving behind the carbon and 

 lime while liberating oxygen. The hydro-carbons are afterwards 

 oxidized in the respiration of animals that feed upon the plants, 

 and secrete structures of limestone. 



Phosphoric acid and fluorine have slight chemical affinity, yet 

 they are continually foond associated in mineral deposits. Phos- 

 phate of lime and fluoride of calcium offer nearly equal resist- 

 ance to solution by atmospheric and aqueous agencies. The first 

 is a constant constituent of marine plants ; both are found in the 

 lower marine animals, and by their means are presumably 

 brought together again in rock formation. Land plants and 

 animals take a frequent part in this circulation. Disintegrated 

 recks form soil-supporting vegetation afterwards eaten by 

 animals, whose digestive processes bring the substances in 

 question into the more soluble states, in which they are most 

 readily carried to the ocean. 



The sea contains much dead organic matter, and in decom- 

 position the sulphur of the sulphates and of the albumen plays 

 an important part. As to the sulphates, the direct process 

 of their decomposition in decaying organisms may be stated 

 thus : — The carbon of the organic substance takes the oxygen 

 from sulphuric acid and its base, giving a sulphide of the 

 base and free carbonic acid ; water and carbonic acid decompose 

 the sulphide again^ giving sulphuretted hydrogen and a car- 

 bonate. Oxidation of the sulphuretted hydrogen gives sulphuric 

 acid, which in time, uniting with lime, completes the circuit of 

 sulphur. On land the processes are far more intricate. It is 

 probable that in the circuit of sulphur in marine organisms is to 

 be found the key to their powers of eliminating from sea-water 

 the heavier metals. The habitat of marine plants is determined 

 by ocean currents, the growth and development being dependent 

 upon freedom from such disturbance. Animal life follows 

 vegetable. The accumulation of organic existence at certain 

 localities in the ocean — as for instance the sargossa — determines 

 there, in the process of its decay, the position of the material of 

 rock formations, including the heavy metals which have been 

 thus eliminated from their dispersion in sea-water. A thorotigh 

 and minute chemical analysis of the earth brought up by the 

 soundings of the Challenger and the Tuscarora, would be apt to 

 throw light on some of the details of tJhese problems. 



The "Difference Engine," a calculating machine devised by 

 Mr. George B. Grant, and now in course of construction for the 

 University of Pennsylvania, was described by Prof. Fairman 

 Rogers. The frame of the machine is 8 feet by 4 feet. To this 

 frame are attached, though removable at will, 100 similar parts 

 or elements, each of which is a small adding machine, repre- 

 senting a single decimal place during operation. When these 

 elements are combined in groups, each group represents a certain 

 difference of numbers, such as by consecutive additions to a 

 starting number gives the required mathematical table or series. 

 The difference thus added may be constant or variable. A table 

 of squares is made by adding two differences, one constant, the 

 other variable ; cubes add three differences of which only one is 

 constant. Logarithms are obtained similarly, though the opera- 

 tion is more complex In this machine certain groups of elements 

 are set to constant differences, and transfer their products in 

 figures to other groups, which in turn transfer their variable 

 values to groups above them. Babbage's machine was more 

 costly, and Scheutz's more complicated than this ; its chief 

 advantages are : interchangeableness and ease of grouping of the 

 elements, a constant introduced by simple apparatus in each 

 element ; an improved method by which the figure produced by 

 any element is sent to the corresponding element in a higher 

 group, and gr, atly improved arrangements for the operation of 

 "carrying." The main figure- wheel of each element is moved 

 forward by a carrier, which is released at the proper point by an 

 inclined edge that takes it out of the way of the wheel. When 

 a carriage is to be made, as for instanct, if the wheel be at 8 and 

 3 be added, making 11, the next wheel standing at o, which 

 must be turned to i, is so contrived that at the proper moment 

 its inclined edge is slipped one tooth forward, and the carrier 

 moves that wheel one step further than it otherwise would. This 

 principle is so extended to successive carriages that if a long row 



