TRACT 26.

MEAN DENSITY OF THE EARTH.

OJ the measure of the base rb" in Glenmore, the valley to theSouth of Shichallin, taken the 1 6th, fife, of Sept. 1774.

Here a and b are the names of the two measuring rods,which were laid down alternately in the order as expressed inthe following table of measures. The lengths of these rods,by the brass standard, when the thermometer was at 62-J-,were thus, viz, •

A = 20 feet 1-255 inch. = 20-10158 \ ^

B = 20 feet 1-323 inch. = 20-11025 1

The numbers following each rod, with the sign -j- interposed,are inches and decimal parts; and they denote the distancebeyond the end of each rod to the, beginning of the next fol-lowing rod; and therefore the sum of all these numbers -mustbe added to the sum of the lengths of the rods themselves,for the total of the measures. Also, as the first rod began at2 feet 8 inches from the point r, this number is to be addedto the total last mentioned, to give the measure of the wholebase from r to b".

a + S'29b + 2'33

A + 6* 1 1ji + 6‘66

A+ 2-79

B+ 1-20

a+ 2-07b + 4-80a+ 0-00b + 1-78a+3-29b + 2'85a+ 6-39b + 4-86A + 6-08B + 8-58A + 9-07B + 1 -53A + 2-2sB + 7'47a + 2-40

b + 3-42a+ 7-42b + 8-14a + 8 - 77b + 3-45a + 3-80b + 6 84a + 7-76b + 3-28a + 4-87

B + 0-18

a 8-7(1A + 7 87D + 4-73a + 6 56B + 5*24a + 7*90b + G-32a+ 692B + 7-28A + 6*34

c + 8-93a -I- 5-39li + 3-20A + 3'54B + 1-26A +3-20B + i'34A+ 3-74b + 7-22a + T91B + 4 - 46a+ 195b + 2'26a + 454B + 4-4Sa + 3-14n + 3'38a+ 5(0b + 4 -85

A + 6’ 12

B + 3-44

a + 6*18b + 4-19a + 4 51n + 3 (HA + 437b + 2-96a+ 2-47II + 3-90A + 5-78n + 3-97a + 4-87B + 4-S3A+ 3-84b + 3-65a + 6-96b + 3-07a + 3-55b + 2-93a + 553B + 5‘33a + 4-33

ii + 3-67a + 5'12B + 1-06a+5 96B + 2-47a + 3-84b + 5’57a + 0-63B + 7-41a+3-11b + 1 '74a + 207b + 4'33a + 593B + 6-36a + 4'47B 4 3-75a +4-74B + 3-06A + 2'58b + 4'15

a + 3-16n + 4'64a + 3-26'b + 4-18a + 4 04B + 2-92a + 3-10b + 5-11a + 4*61■ E + 3*34A + 2’57B + 5*80A + 3*37b + 2’58a + 2’24B + 3*48a + 2-95B + 2*88A + 3*69B + 4*07A + 2-75

b + 4-65A+ 4-07B + 3*23a + 4-16B + 5-73A +4-12b + 4-91a+ 3-18b + 3-91a+ 5-28B + 2-90A+ 4-39*b + 4-37a+ 3 29B + 2-12A + 2-95b + 3-30a + 2-82b + 3'97a + 1-37

B + 0-00

The sum of all these is 74a + 73b + 669-28 inches,

or 74a + 73B + 55-773 feet, includ-ing the 2 feet 8 inches at the beginning of the measurement.