Of the Bogs in Ireland, 443 



dimensions, the engineer must consider how the district 

 may best be subdivided. 



" 3d. The engineers are in all cases, both in their maps 

 and in their reports, to express the contents of the bogs, 

 both in Irish and English acres, and also to insert in their 

 maps, scales of both Irish and English miles. 



" 37. The commissioners not judging it expedient for 

 the present to lay down a meridian for the purpose referred 

 to in the twenty-eighth article of their instructions, consir 

 der it sufficient that the engineers should construct their 

 maps upon the magnetic meridian, the north of the mag- 

 netic meridian pointing to the top of the map, and the me- 

 ridian line being parallel to the sides of it. 



M 38. The estimates referred to in the seventeenth arti- 

 cle of the Instructions, arc to include all the expenses, 

 which in the jui .'..■■ c men t of the engineer will be necessary to 

 reduce the bog to such a state that it shall be ready to receive 

 agricultural improvements. These estimates are however 

 to distinguish the expenses of the different descriptions of 

 works, and or the different classes of drains recommended. 

 By order of the Board. 



Dublin Society House, B. M c CUrTHV, 



M& y 16 » l8l °- Set* to the Commissioners. 



To Mr. Tilloch. 



Sir, — Having as an exercise, by direction of my father, 

 reduced Mr. Richard Griffith's large section across the Bog 

 of Lullymore, so &s to agree in scale of length and in po- 

 sition nearly, with his map of this bog, printed in the 1st 

 Report to Parliament on the Bogs in Ireland, from which 

 you gave some extracts in your last number, and distin- 

 guished therein alkthe proposed drains, and shown by ar- 

 rows whether they run northward (up) or southward 

 (down), I ta£e the liberty of sending a copy, and perhaps 

 you may deem the same worth a plate in a future number of 

 yourMagazine, in order to explain, as it does (see Plate X.), 

 the uneven surface and variable thickness of the peat in 

 these vast bogs, the uncertain thickness and existence of 

 the alluvia] yellowish blue clay, (No. 10. in your last num- 

 ber, p. 371,) on which the peat frequently rests, and the 

 very uneven and undulating form of the great bed of allu- 

 via, clayey limestone gravel, of vast thickness, which forms 

 the floor and borders of this and most others of the bogs of 

 this part of Ireland^ except in a few places where strata 



appear,. 



