36 British Association for the Advancement of Science. 



timber frame. This was obviated by making the side of the 

 vessel solid for twelve inches before and aft the bulk-head, and 

 closing up the interstices with felt. As to the number of these 

 compartments, he had found, after several trials, four bulk-heads, 

 forming five sections, unexceptionable. The length of these sec- 

 tions was arbitrary ; Mr. Williams made the centre one enclose 

 the machinery, and those at the stem and stern of comparatively 

 small length. He had, two days before, tried several experi- 

 ments with the Royal Adelaide, having admitted the water by 

 boring holes, first into the foremost section, next into the second, 

 and afterwards into the third ; and in each instance very little 

 depression had been produced in the stem, never exceding twelve 

 inches, while there was no disturbance to the men at work. In 

 cases of fire, too, there was a double advantage from this arrange- 

 ment ; the fire could not extend far under deck, so that the men 

 could work easily in extinguishing it, — ^there would be no cur- 

 rent of air throughout, and the water might, if necessary, be ad- 

 mitted to the section attacked by the fire, without any general 

 inconvenience, and without any danger. Mr. Williams intimated, 

 in conclusion, that a vessel would be placed by the Company at 

 the disposal of members of the Association returning to Ireland, 

 as it had been to transport them to Liverpool. — The President 

 then closed the meetings of the Section, by a few remarks on the 

 successive development of power apparent in it. Though ori- 

 ginally only an offset from another Section, it now rivalled, if it 

 did not exceed any of the others, in the variety and interest of 

 the topics discussed, the attendance of members, and the ability 

 of the papers laid before it. He, as its original proposer, felt es- 

 pecially interested in its progress, and hoped to see it still more 

 distinguished. 



Heat of the Earth. — The sun's heat was found to extend to vari- 

 able depths at various places, and with many alternations of increase 

 and diminution ; and it was in general necessary to descend from 

 one to two hundred feet before the eflect of this cause disappeared ; 

 from thence downwards, the evidence of an increasing tempera- 

 ture seemed to be quite satisfactory. At a colliery at Wigan, 

 where the surface mean temperature was 50°, at 50 yards deep 

 the temperature was constantly 53° ; at 150 yards deep the tem- 

 perature was 56.75° ; at 250 yards 63°. From this set of ob- 

 servations, it appeared that a descent of 100 yai'ds was accompa- 



