Of the Bogs in Ireland. 4 4 1 



the engineer is to take into consideration the propriety of 

 draining it by means of wind-mil] pumps or other ma- 

 chinery ; the expense of erection, and annual charge of 

 which, he will include in his report. 



" 25. The engineers are further to consider what situa- 

 tions may best answer for the corn- mills which may become 

 necessary, in consequence of the increased tillage of the re- 

 claimed districts, and how far the water of the drains may 

 be used in working them ; and they are particularly to in- 

 quire as to the situations and circumstances of such mills 

 already in existence, the supply of whose water may be af- 

 fected by the projected drainages, and to consider and re- 

 port, whether it be most expedient to provide reservoirs for 

 their supply, or to purchase the interest of the proprietors. 



" 26. They aie also particularly to report, where any of 

 the proposed works appear likely to diminish the supply of 

 water for the Grand or Royal Canals, or other navigations, 

 or to interfere with their levels or embankments ; and in 

 what manner such injuries may be best obviated. 



f* 27. In order to connect the respective purveys with 

 each other, and to enable the commissioners to judge how far 

 these drains may be applied to the purposes of internal na- 

 vigation, they propose to direct, that the engineers to whom 

 the districts nearest to Dublin may be allotted, shall ascer- 

 tain with the utmost accuracy, the difference of level be- 

 tween the levels in their maps, and of the platform on the 

 capital of the column erected in the memory of Lord Nel- 

 son ; and to communicate the difference of level to the en- 

 gineers who may have districts immediately beyond them, 

 for the purpose of carrying forward the comparison. The 

 commissioners intend afterwards to request the Ballast Of- 

 fice to mark at the Pigeon House Dock the level of high 

 water in an ordinary spring-tide in the Bay of Dublin, so 

 that by determining the difference of level between that and 

 the platform on the column, the difference between the level 

 of the sea and the various levels which are to be taken in pur- 

 suance of these instructions, may be correctly ascertained. 



" 28. To enable the commissioners to complete the con- 

 nexion of the surveys by trigonometrical observations, if 

 such should hereafter be deemed expedient, the engineers 

 are to have permanent marks at the extremities of the several 

 levels, and to lay down all remarkable objects which are 

 likely to be permanent, such as raths, towers, castles, 

 cairns, hill -tops, market-houses, &c. 



u 29. The various lines cf levels are to be shown on the 

 map by dotted lines. 



" 30. The 



