Notices respecting Netv Books. 287 



To obtain Taylor's theorem, x must be regarded as entirely 

 dv 

 mdependent of 2- or^=0. In this case the differentiations 



will not be affected by entirely separating them from the inte- 

 grations, so that the fundamental development becomes 



Y{^ + w)-Yz=¥z.x + Y"z.~ -^&c., 



XLII. Notices respecting New Booh. 



An Account of the Measurement of the Lough Foyle Base in Ireland, 

 with its verification and extension by Triangulation ; together with 

 the various methods of Computation followed on the Ordnance Survey, 

 and the requisite Tables. By Captain William Yollond, of the 

 Royal Engineers, F.R.A.S. Published by Order of the Honourable 

 Board of Ordnance. 



IN our Number for January 1843, we announced the publication, 

 under the authority of the Board of Ordnance, of a volume con- 

 taining the observations of stars made with Ramsden's zenith sector, 

 at ten different stations on, or connected with, the arc of meridian 

 which extends from Dunnose in the Isle of Wight to Balta, in Shet- 

 land.^ It was announced in that volume, that the triangulation was 

 then in so forward a state that the printing of the geodetical obser- 

 vations would shortly be commenced. Though five years have elapsed 

 since that announcement, the triangulation, it appears, is not yet 

 completed ; and in the mean time we are favoured with the present 

 volume, giving an account of the measurement of the Lough Foyle 

 Base, preparatory to the survey of Ireland, with the detail of nu- 

 merous experiments on the expansion of metals and comparisons of 

 various standards of measure ; a description of the methods followed 

 at the Ordnance Map Office in the computation of the triangulation, 

 and of the altitudes, longitudes, latitudes, and bearings of the stations; 

 together with sundry tables for facilitating the calculations. This 

 base, it is to be observed, was measured in 1827 and 1828, that is 

 to say, twenty years ago. Why the account of the measurement 

 was not given sooner, or why it is given at this part'cular juncture 

 without the triangulation, does not very clearly appear; but the 

 delay which has taken place cannot but be regarded as unfortunate. 

 Of the officers who were concerned in the operation, the two who 

 took the most active and i)r()mincnt part (Cajjtain Druminond and 

 Lieutenant iMurjihy) have died ; others have retired from the service ; 

 and the conseciueiicc is, that the description, both of the apparatus 

 and the details of proceeding, docs not come from one who was j)er. 

 Bonully engaged in the operation, and who could supply deficiencies 



