R. A. Daly — Mechanics of Igneous Intrusion, 277 



expansion (according to the curve) as solid bodies, but at 1400° 

 C. Col. 4 gives the specific gravities under the conditions of 

 col. 3, but calculated from the expansion coefficients of Reade.* 

 It follows from this calculation that, if average sandstone, 

 marble, slate, and granite should expand uniformly as solid 

 bodies to 1400° C. and according to the rates set forth in those 

 coefficients, the rocks would expand respectively 4*2, 4*1, 3*9 

 and 3*7 per cent in volume. The increase for diabase under 

 similar conditions but calculated from the ratio of expansion 

 in solid diabase as determined by Barus, is 3*6 per cent, These 

 figures and a comparison of cols. 3 and 4 indicate a remarkable 

 agreement in the results of quite independent experiments 

 using different methods. It will be noted that col. 2 is carried 

 out only for the plutonic massive rocks with which we are here 

 chiefly interested. Further, the legitimacy of extending that 

 column to cover the sediments and schists may be questioned, 

 although the isolated experiment of Delesse on gneiss (Table 

 III) seems to show a thermal expansion behavior for gneiss 

 comparable to that of the standard diabase. In the prepara- 

 tion of col. 4, Reade's coefficient of marble was used for the 

 limestone and dolomite, his coefficient of slate for shale and 

 phyllite, and his coefficient of granite used for the other crys- 

 talline schists and for the more acid igneous types. In cols. 

 2 and 3, a minimum of error adheres to the figures for types 

 a to d, inclusive, which are most nearly allied in composition to 

 diabase. 



Table IV. 

 1. 



2, 



a. 

 b. 

 c. 

 (I 

 e. 

 f. 

 9- 



Eock-type. 



Peridotites 

 Gabbros 

 Average gabbro 

 Diorites 



Elaeolite syenites 

 Common syenites 

 Granites 



Eange of 



sp. gr. at 



20° C. 



2-90-3-35 



2-80-3*20 

 3-10 



2-70-3-00 

 2-45-2-60 



2-60-2-86 

 2-60-2-73 



Eange of 

 sp. gr. at 

 1400° C. 

 (molten). 

 2-42-2-80 

 2-34-2-68 

 2-59 



2-26-2-51 

 2-06-2-17 

 2-17-2-39 

 2-17-2-28 



Eange of 



sp. gr. at 



1400° C, 



(solid) from 



fusion 



curve. 



■80-3-23 



■70-3-09 



h. Sandstone and quartzite 2-15-2-75 



*. Pure limestone 2*72 



j. Pure dolomite 2 - 87 



k. Shales and clay slates 2-40-2-80 



I. Average phyllite 2*75 



m. Gneisses 2-60-3-00 



n. Mica schists 2-75-3-10 



o. Amphibolites, etc., 2-80-3*30 



* Origin of Mountain Eanges, p. 110, 



61-2-90 

 36-2*51 

 51-2-76 

 51-2-63 



4. 

 Eange of 

 sp. gr. at 

 1400° C., 

 (solid) from 

 Eeade's 

 coefficient. 



2*36-2 '51 

 2-51-2-76 

 2-51-2-63 



07 



63 



77 



31 



65 



50-2 



65-2 



70-3 



2-65 



2-70 



•90 

 99 

 19 



2-06 



2-62 



2-76 



2-30-2 



2*64 



2*50-2 



2*65-2 



2-70-3 



2*64 



69 



90 

 99 

 19 



1886. 



