E. L. DeForest on Reducing Meteorological Observations. 317 
fourth place, a degree of refinement which would be practically 
useless, ‘I'he computation, however, was carefully made to six 
places, so as to secure the nearest value for the last figure. 
rejecting the fifth and sixth places, care has been taken not to 
impair the condition that in any single equation the sum of .the 
three decimal coéfficients must be zero. The first and seventh 
equations, as computed to six places, are 
oe 003668 m,+-003060 m,5—-006728 m, 
1,—=m,-+'002541 m, —:019981 Me "4017440 Mg. 
sega these are reduced 6 four places in the usual way, they 
beco 
M,=m,+:0037 m,-+ 0081 M15—'0067 m, 
M,=m,+'0025 m,~:0200 m, +°0174 mg. 
The sums of the three decimal coéfficients differ from zero to 
cient Maa is least altered by it, as compared with its true value 
to six place 
Since the’ length of a calendar year is either fs or 366 days, 
th > assumption that the year consists of 365°24224 days is not 
year. But the average pe tuk ot a considerable number of con- 
a eereloeial phenomenon, as the mean daily 
temperature ford instance, has been found for a given plac 
the metho mean months, and it is required to interpolate 
The abscissa must be reckoned up to the middle of the ar be- 
Am. Jour. Sct.—Szconp Series, Vou. XLIII, No. 129.—Mary, 1867. 
41 
