. Deep borehole surveys and problems. Boring. 102 DEEP BOREHOLE SURVEYS AND PROBLEMS clear from Figs. 52 to 56 showing the phials, guide tubes and clinometer. The phials contain liquid gelatine. Clear glass phials (Fig. 52) nearly filled with a hot solution of gelatine and each containing a magnetic needle in suspension, free to assume the meridian direction, are encased in a brass protecting tube, let down to the required depth and allowed to remain for several hours until the. Fig. 52.—Gelatine phials. gelatine has set. On withdrawal the phials are replaced at the same angle, at which they c
. Deep borehole surveys and problems. Boring. 102 DEEP BOREHOLE SURVEYS AND PROBLEMS clear from Figs. 52 to 56 showing the phials, guide tubes and clinometer. The phials contain liquid gelatine. Clear glass phials (Fig. 52) nearly filled with a hot solution of gelatine and each containing a magnetic needle in suspension, free to assume the meridian direction, are encased in a brass protecting tube, let down to the required depth and allowed to remain for several hours until the. Fig. 52.—Gelatine phials. gelatine has set. On withdrawal the phials are replaced at the same angle, at which they cooled, by means of the congealed surface seen through the sides of the phial; this is brought to the horizontal. Revolving the phial upon the part where the magnetic needle is seen embedded in the gelatine, until the needle is again in the meridian, the phial is then in the same position, both as regards inclination and azimuth, as it was when its contents con- gealed. Thus we get the gradient and bearing of the bore- hole at that spot, and these are measured by means of an angular instrument constructed by the inventor. The mean of the several phials gives a more accurate result. By repeating this operation at measured intervals through- out the borehole, its course is Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Haddock, M. H. (Marshall Henry). New York, McGraw-Hill
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