ON SUn-WJKALDEN EXl'LOKATION. 191 



It being found impossible to lore (and that tbo drilling by the T chisel in 

 ordinary use so crushed up the debris as to baffle examination), the Honorary 

 Secretary designed a novel form of drill possessing the following advantages : — 



1st. It cuts only the circumference, 



2nd. It makes better progress. 



3rd. The central core is left intact. 



4th. The tool not unfrequently extracts the core itself. 



The gypsum shovrn was thus extracted. No such cores have, it is believed, 

 in this country been brought to the surface from similar deptlis. 



A plan of an ingenious form of electromagnet for the extraction of broken 

 pieces of steel from the bottom of the bore-hole M'as exhibited. It was suggested 

 by J. R. Capron, Esq., of Guildford, and designed by Professor John Tyndall, 

 F.R.S., assisted by Messrs. Tisley and Spiller. 



The question of cost is a serious one. The only definite contract for con- 

 tinuing the work from a depth of 218 feet to 1500 feet (including the use 

 of the tools, machineiy, engine, &c. belonging to the Committee) was over 

 £5000, When an application for a grant was made in 1872 a large sum 

 was not asked for, and i't was deemed more consistent to await the first 

 year's report ; not only has the £25 voted been expended, but over =£2000 

 has been subscribed by other parties, aU of which wiU have been expended 

 before the expiration of the current year ; large additional subscriptions wiU 

 therefore be required. 



A reference to the names forming the Central Committee will convince 

 that the best method for ultimate success will be adopted. 



It is therefore hoped that the Association will consider it advisable to 

 reappoint the Committee, and to vote an increased grant for the prosecution 

 of the work. 



In addition to the actual cost of the work of the boring, the expense 

 incurred has much exceeded the estimate. This excess is attributed to the 

 foUowiug causes, many of which will not again occur : — 



I. The increased diameter of the bore. 

 II. The distance travelled by the engineer. 



III. The cost of shelter in so exposed a situation, it being impossible to 



get men to work A^dthout it. 



IV. The cost of carriage, from the inaccessible nature of the roads &c. 

 V. The large increased cost of fuel. 



VI. The necessity of providing forge, tools, &c. in anticipation of future 



demands. 

 VII. The original expenses of sui'vey and commencement. 

 VIII. Printing and postage in soliciting subscribers. 



Geological Bepori, drawn up hy W. Topley, F.G.S., of the Geological Survey 



of England and Wales. 



Hitherto almost all borings have been made for the purpose of solving some 

 probable anticipation, or for the discovery of something definitely required, 

 as coal or water. In such cases, if the object sought for be found, the boring 

 is said to be successful ; if not, it is said to have failed. With the Sub- 

 Wealden boring, however, failure can only arise by a premature arrest of the 



