XIV INTRODUCTION TO THE MAKERSTOUN OBSERVATIONS, 1843. 
TABLE 1.—Values of one of the Long Scale Divisions. 
Observer B. Observer W. 
Mean of Value of Mean of Reale Mean of Value of 
Mean of 
al Scale 
EMG three Dione three one secs three Divitions three one 
Division. : a cee . Y acs 
Verniers. Verniers. Division. Verniers. Verniers. Division. 
° , ” ° , u , ° , u ° , ” , 
160 | 55 18 46-25 54 11 34-17 | 0.67201 180 | 54 59 9-17} 280 | 53 51 51-25) 0-67300 
170 | 55 12 4-17 54 4 50-21} 67233 190 | 54 52 22.50) 290 | 53 45 7-50) 67250 
180 | 55 5 20-83 53 58 2-50] 67305] 200 | 54 45 38-33) 300 | 53 38 25-00| 67222 
1st series, observer B; one long scale division = 067247 
2d series, observer W 3 cercsecssseeeeeceeeee see ce » = 0°67257 
The adopted mean value of one division of the long scale of 500 divisions = 0-6725.* 
Aug. 5. 1843. A short series of observations was made to determine the value 
of one division of the short scale of 300 divisions. 
Three verniers read ; measures of 50 divisions ; one division of the short scale 
0°'7504 B. 
Ss { 0-7502 } ; observer (Ww. 
Nov. 29. 1843. Two series of observations were made with one vernier. The 
readings in the following Table are the means of the readings by Mr WELSH and 
myself. 
TABLE 2.—Values of one of the Short Scale Divisions. 
First Series. 15, Second Series. 3, 
bet k aee Value of | gcale ae Be Scale Velkate Value of 
Se? Se pone) | Divasion. |e cr - 5 | Division: |p ita Staee one 
Division. Division. | 
Scale 
Vernier B. Division 
Cr " Cyt ” , pa? ” , 
55 26 56-5 54 49 27-5 | 0-74967 54 11 28-0 53 34 2:5 0-74850. 
55 19 26-0 54 41 57-5 74950 54 3 58-5 53 26 31-0 
55 11 56-0 54 34 27:5 74950 53 56 30-0 53.19 2-5 
55 4 3-0 54 26 52-0 75267 53 48 55-0 2 53 11 35-0 
54 56 55-5 ‘ 54 19 23-5 75050 53 41 32-5 53 4 3.5 
1st series ; one division of the short scale of 300 divisions = 07504 
Qd'weriesi! ste. dseenceee Yass as eh Me oated te doe’ Pet eis = 07486 
The anne value of one division of the heck scale = 07500. 
* The differences in the partial results, it is believed, are not due to errors of graduation of the 
x, 
scale, as different comparisons give different results. If greater accuracy could be gained in the read- 
ings of the horizontal circle, it is obvious that the mean of the angle subtended by one or two hundred 
scale divisions ought not to be taken as the value of the angle subtended by one scale division, 
