TOTAi SOLAE ECLIPSE OF JULY 18, 1860. 
391 
Nos. 22 and 28 . 
Nos. 22 and 29 . 
Nos. 23 and 28 . 
Direction of motion of 
moon’s centre. 
297 15 37-3 to II7 15 37*3 
297 8 53-6 to II7 8 53*6 
297 2 I4-I to II7 2 I4-I 
Nearest 
approach 
of centres. 
12- 03 
11-27 
13- 29 
Eelative 
motion of 
centres 
per minute. 
27-84 
27- 78 
28- 02 
Middle of 
totality. 
li m sec. 
3 2 16-4 
3 2 18-4 
3 2 20-9 
Mean . . 
297 8 55 II7 8 55 
12-20 
27-88 
3 2 18-6 
The following a 
ire the numbers computed for the same elements by 
0 / o / 
U 
// 
k m sec. 
Carrington . . 
297 17 0 to II7 17 0 
13 
27-27 
3 2 19-5 
Farley . . . 
12-7 
27-35 
3 2 20-0 
Table IV. 
In Table IV. column 1, are given the computed sines of half the angles of the opening 
of the cusps, which are set forth in column 12, Table III.; the sun’s mean measured 
radius, namely, 1904'91, being employed in the computations. The resulting numbers 
correspond to the semichords given in Table II. column 10 ; but in most instances the 
calculated is greater than the measm'ed semichord or sine. 
In column 2 are given the cosines of the same angles referred to the sun. These 
numbers correspond to the distance of the sun’s centre from the imaginary chord joining 
the cusps. 
In column 3 is set forth the augmented semidiameter of the moon for the epoch of 
each photograph, the increase or decrease from the mean measured diameter 2002‘2 
being derived from Mr. Faeley’s values. 
Calling the sines in column 1=«, and the augmented lunar semidiameter '=5, the 
cosine of the moon for the angle represented by the same sine was derived by the formula 
—a){b-\-a); column 4 gives these cosines referred to the lunar radius, and repre- 
sents the distances of the moon’s centre from the chord joining the cusps. 
The distances of the sun and moon’s centres could evidently be derived by taking out 
the sums or diflFerences of such numbers as those in columns 2 and 4 : in the cases actually 
under consideration, the distances of the moon and sun’s centres result from the addition 
of these quantities ; they are given in thousandths of an inch in column 5, and reduced 
to seconds of arc in column 6. 
In column 7 are given the like quantities, derived from measurements of the distance 
of the peripheries, which are merely a repetition of the values given in Table III. 
column 6. 
In column 8 are set forth the mean distances of the centres of the sun and moon, 
ascertained by taking the arithmetical mean between the numbers in columns 6 and 7. 
In column 9 are the same distances computed by interpolation of the values calculated 
by Mr. Farley. 
3 G 2 
