Hinks bhava Moone ams. | 395 
«Wari this mesh equatorial dearéé “ef60460 fathoms, and'the thea 
) ellipticity OF east =u), ‘the’ degrees of 1ddvede, ° and of the’ pétpéndicalar to 
“the tmeridiahs” were calcule ated by niéans- of Colonel” Linton’ S formule, 
for latinas 30! Bp ‘and 59, being’ the lindits of the ‘survey. “The tesults 
axé\ given ih tables’1) 2. Tables, gives ‘the difference of the degrees of 
latitude; and obliane degrees calculatéd from the’same Data bs y means of 
Mr. Daxey’s formule given in the 2d Volume, trigonometrical * survéy of 
England and W ales.* ‘These tables will be often referred to. | 
yo Jone 1 SHO JOLIGVAGS YISY & 9G 7 
As Wauen from given distances anid Azimutis we'are to. calculate differ= 
-encesof longitude and: latitudéyaiy’ attention’ to the® ‘real! figire ‘of the earth 
is required 206 avoid ébrisidcbabte! share! sag eviderit frum’ le manter in 
whieh lotieittides'and latiiwaes ‘Ue eekoned Ywhen however we are ‘bo cal- 
oulatethe dide$ahd a of triangles of comparatively ‘small extent, “it 
is” Pelctiait thts Ddisteedra of the deviation of the figure from a sphere can- 
not osdasiGn “any bho ‘Distances fnerciore on the ‘ellipsoid if they’ ‘be 
not too great, may b be detentiitied by supposing ‘them referred to a sphere. 
This iS an important distinction: and not to be forgotten. “The Fesolution i 
of ‘sinall’ spheri¢al triangles has "been madé equally simple, as th hose on hy 
plane} by the beautiful theorem of Lecenbae, in which he proves that b y 
a y 
deducting SoPthe Axcess OF" the ihre’ ‘spherical ang es above 180, from 
ike Sieigoleo od al Ot. (iSe4eS03h Heed wee i i 
ether iL 9 + eee z {j rap) ‘Of } a3 L393 Jail es A F 
2 Ture are shorter and more convenient formula ALOE however), which were not so 
familiar at the time as those used which are strictly corfect. |\ 0) 040" 
+ Ir has eas demonstrated by M. Lecenpne, that the difference between the spherical and 
sg angles in’ the largest triangles that occurred i in the French survey, does not amount to 
vo of a second. 
