314 Geological Society : — 



the quantity of fluid in the chamber, and ten inches of graduation 

 are found to be ample under all circumstances. By thus taking all 

 the readings, so to speak, on the balance, a uniformity of proceeding 

 is secured, which is not without its value. The instrument, con- 

 structed according to the dimensions here given, will denote the in- 

 tensity of the noonday sun at the summer solstice near the sea-level 

 in England by about 100 divisions of the scale. 



Owing to the difficulty of shading satisfactorily, and anomalies 

 found to occur in observing among the snow-fields on the high crests 

 of the Alps, the following contrivance has been adopted : — 



A plain telescope-tube of bright metal, 18 inches long and 2| 

 inches in diameter, open at both ends, is pierced in its central section 

 with a circular hole 1^ to \^ inch "in diameter, from which springs 

 a flanged shoulder projecting about ^ inch to receive a perforated 

 split bung, which clasps the thermometer-stem and holds the bulb 

 firmly in the centre of the axis of the tube. Two caps, fitted at the 

 ends with clean plate-glass, are made to slide off and on at the two 

 ends to admit of the glasses being readily wiped. By protecting 

 these with a little wadding, the tube serves as a case for two acti- 

 nometers. In the central section of the tube, made by a plane per- 

 pendicular to its axis, and nearly 90° from the centre of the circular 

 hole, is a screw to attach the tube to an altitude and azimuth motion, 

 by means of which it may be kept constantly directed towards the 

 sun. Below the joint is provided means of attachment to an alpen- 

 stock or ice-axe. The shading is effected by means of a loose-fitting 

 cap, bottomed by a chamber with air-holes. The shadow of the large 

 thermometer-bulb on the lower glass, or on a plane held beneath it, 

 is a guide to a perfect adjustment in the working of the instrument. 



GEOLOGICAL SOCIETY. 



[Continued from p. 234.] 



January 23, 1867.— Warington W. Smyth, Esq., M.A., F.R.S., 



President, in the Chair. 

 The following communications were read : — 

 1. "On the occurrence of Consolidated Blocks in the Drift of 

 Suffolk." By George Maw, Esq., F.G.S., F.L.S., &c. 



As a contribution to the evidence on the geological position of 

 the blocks of saccharoid sandstone scattered on the surface of 

 many parts of the Chalk-districts, which appear to have been derived 

 from several formations of different ages, the occurrence was recorded 

 of large isolated masses of consolidated sand and gravel in the Drift 

 intervening between the Chalk and Boulder- clay of the high ground 

 of Suffolk. Many of the masses are several tons in weight. 

 Although they occur at a general level, they do not form a con- 

 nected band, loose Drift, out of which they were evidently com- 

 posed, forming a horizontal continuation of their strata. The 

 Drift is largely charged with Chalk- detritus, which also occurs in the 

 softer blocks. Some of the blocks are extremely hard and compact ; 





