96 Correspondence and Miscellaneous.^ 



The total expenditure upon the whole boring, 4051 feet (5570 

 English feet), both by manual labour and by steam power, was 

 about £8717 14s. — making the average cost for every Prussian foot 

 in depth about 2 guineas, or £1 lis. 4d. per English foot. 



The whole time spent on the work was 51^ months, or 4 years 

 and 3^ months ; but as there was an interval of 5 months, between 

 July, 1868, and January 1871, during which period the boring 

 operations were suspended, the actual number of working months 

 becomes reduced to 46|-. 



The process of boring throughout was by percussion borers worked 

 by rods ; and the rocks bored through belonged to the Triassic series. 



The progress of the work would have been much greater but for 

 the accidents which took place, and for the delays which were caused 

 by the observations that were made as to the increase of the tempera- 

 ture of the earth in depth, etc. 



The measurements were taken in Prussian feet; these have been 

 reduced to English feet — the Prussian foot being 12-357 English 

 inches. 



A memoir ('•' Die Tiefbohrung zu Sperenberg ") on the subject of 

 this interesting undertaking will be found in the " Zeitschrift fur 

 das Berg- Hiitten- und Salinen-Wesen in dem Preussischen Staate," 

 Band xx. 1872. 



H. W. Bristow. 

 28, Jermyn Street, 

 January, 1875. 



THE GREAT RH^TIC BONE-BED NEAR FROME. 



Sir, — To those of your readers who make a special study of the 

 Phytic beds, it may be of interest- to know that the great Bone-bed, 

 situate in the Black Shales of the above series, and replete with its 

 usual remains, has been met with at the depth of 310 feet, in a pit, 

 at present being sunk by James Oxley, Esq., of Frome, to the Lower 

 Series of Coals of the Somersetshire basin, about two miles N.W. of 

 Frome, and on the S.E. flank of the Mendip Hills. 



Alfred C. Crutwell. 

 West Hill, Frome, 

 15 Jan. 1875. 



IIVCIS C E IL. liJLlSrSOTTS . 



Artesian Well at Torquay. — The Diamond Boring Company 

 are sinking an artesian well on the premises of the Torquay Brewing 

 Company, in Fleet-street, Torquay. About 90 feet of solid limestone 

 (Devonian) has been penetrated. It is anticipated that an abundant 

 supply of water will be reached at a depth of about 200 feet ; but 

 although this may be regarded as very problematical, there is no 

 doubt that if the work proceeds a very interesting geological section 

 will be obtained. 



