Experimental researches on the granites of Ireland / by Samuel Haughton.

  • Samuel Haughton
Date:
1858
Catalogue details

Licence: Public Domain Mark

Credit: Experimental researches on the granites of Ireland / by Samuel Haughton. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

    5/8 page 303
    No. 3. Granite from Goragh Wood station, north of Newry, medium-grained, composed of quartz, white felspar and black mica. No. 4. Granite, of gneissose structure, from the cutting south of Goragh Wood Station, medium-grained, composed of quartz, red felspar, and green mica, arranged in a flaky gneissose manner. Table IV.—Analyses of Soda-Granites. 1. 2. 3. 4. 64-60 74-20 62-08 66-56 Alumina 14-64 10-84 15-92 13-52 Peroxide of iron... 6-04 1-88 7-72 6-76 3-16 2-84 5-52 1-20 2-80 Trace 2-16 1-32 3-15 3-12 219 2-73 Soda 4-02 4-77 3-34 3-75 Protoxide of iron. 0-18 Loss by ignition... 1-13 0-83 0-89 2-19 Totals 99-54 98-48 99-82 98-21 The elvan-dike (No. 2) differs from the other three granites in the large per-centage of quartz, which is a general characteristic of elvans and felstones, but agrees with them in the relative proportions of the two alkalies. Reserving the elvan-granite for a separate discussion, I shall now tabulate the atomic quotients of the other granites, which appear to belong to the same family of rocks. Table V.—Atomic Quotients of Soda-Granites. 1. 3. 4. 1-435 1-375 1-479 0-281 0-306 0-260 Peroxide of iron... 0-075 0-096 0-084 0-011 0-019 0-004 0-140 0-108 0-066 0-067 0-046 0-058 0-130 0-108 0-121 Protoxide of iron. 0005 Adding together the silica, peroxides, and protoxides from the preceding Table, I find— Table VI.—Atomic Quotients of Silica, Peroxides, and Protoxides in Soda-Granites. 1. 3. 4. Average. 1-435 1-375 1-479 1-429 Peroxides ... 0-356 0-402 0-344 0-367 Protoxides... 0-348 0-281 0-254 0-294 It is evident from a comparison of Tables I., II., III., with Tables
    digitised image 1
    digitised image 2
    digitised image 3