The Artesian Wells of BriUsh Guiana. 107 



consisting merely of clay with hydra ted oxide of iron and some organic 

 matter derived from the Lamaha water. This deposit is neither adherent 

 nor coherent and we are satisfied that it would be readily removable by 

 flushing out the mains with clean water." Under the new proposition to drill 

 wells of big diameter, it may be possible to furnish an adequate supply 

 for Georgetown from 4 to 6 wells, drilled in the near vicinity of the 

 waterworks, while for Xew Amsterdam one or two wells should amply 

 suffice. 



While I am confident that wells having a hole 32" in diameter to 

 suit the 20" diameter casing with special strainer, can be successfully 

 drilled I cannot disguise the fact that to do so will require everything to 

 be of the best, both in expert drilling and in plant, while there is little 

 doubt that one's ingenuity will be taxed to the utmost. 



The special tool for drilling or enlarging wells from 15" to 32" in 

 diameter has already been designed, and only the final estimate of cost 

 is now awaited, and this should be available m a few days' time. 



In the event of the large diameter wells being adopted in the future 

 for the colony generally, the wells of snfall diameter already drilled will 

 be of inestimable value, as " pilots " showing exactly what may be 

 expected at each individual spot, so that the expensive large diameter 

 wells would not be risked in any way. From this reason alone the small 

 wells should still continue to be drilled as the cheap and necessary 

 pointers for the big wells. The advent of the big capacity wells will at 

 once bring into prominence the question of irrigation, which has been 

 proved to be uneconomical when attempted by wells having only a small 

 bore and flow. There is no doubt that the initial expenditure on any 

 cluster of big wells would be considerably in excess of any pumping plant 

 that could force the same amount of water on to the land, but it must be 

 remembered that water has to be always available to compete against the 

 artesian well, and that while the pump requires motive power and repairs, 

 the artesian well would require neither, so that in the long run, the 

 expense on the wells taken over a period of years would be less than that 

 of the engine and pump. Where a very long supply channel was required, 

 then the artesian wells would be immediately cheaper than the pumping 

 scheme. 



X.B. — Since writing the foregoing the Xabaclis well has been successfully completed at 

 817 feet — an excellent flow of pure water being obtained — with no sign of any sanding up. 

 The problem of the choking of the wells may now be regarded as being definitely solved. 



