222 Permanence of the Rutherfurd Photographic Plates. 



Results of the Measures, Plate 18, Standards (^Continued). 



X-co6rdinate (Rev'd). 

 Circle right i°43 37',' 43 38'! 

 Circle left 43 49, 43 48. 



Desig. 



of 

 Star. 



Microm. Readings. 



Diflf. 



Mean 

 2 



Screw 

 and Div. 

 Error. 



Final 

 Reading. 



Obs'r. 



On 

 Star. 



On Scale. 



Line 



Reading. 



A34,E 

 W 



23 E 

 W 



i8m, E 

 W 



24 E 

 W 



9-5255 

 9-0185 

 9-5440 

 9.0000 



9-5325 

 9-0445 

 9-5285 

 9-0365 



lOI 



100 



lOI 



100 



29 



28 

 29 

 28 



10.9340 

 10.2325 

 10.9520 

 10.2150 



11.4720 

 10.8180 

 I r. 4615 

 10.8030 



1.4085 

 1. 2140 

 1.4080 

 1. 2150 



1.9395 

 1.7735 

 1-9330 

 1.7665 



0.6556 

 0.6558 



0.9282 

 0.9249 



—0.0003 

 —0.0003 



— 0.0006 

 —0.0006 



101.1553 

 IOI.1555 



29.4276 

 29.4243 



D. 

 D. 



D. 

 D. 



Y-co6rdinate (Rev'd). 

 Circle right 271 43 54, 43 51. 

 Circle left 43 28, 43 28. 



Desig. 



of 



Star. 



Microm. Readings. 



Diff. 



Mean 

 2 



Screw 



and Div. 



Error. 



Final 

 Reading. 



Obs'r. 



On 

 Star. 



On Scale. 



Line 



35 

 35 

 35 

 35 



III 

 III 

 III 

 III 



Reading. 



A34,E 

 W 



25 E 

 W 



i8wi, E 

 W 



26 E 

 W 



9-5095 

 9-0385 

 9-5225 

 9-0475 



9-5390 

 9.0270 

 9-5205 

 9.0170 



10.2660 



9-7965 



10. 2840 



9.8090 



9-9335 

 9.4500 

 9.9100 

 9.4400 



0.7565 

 0.7580 

 0.7615 

 0.7615 



0.3945 

 0.4230 



0.3895 

 0.4230 



0.3786 

 0.3808 



0. 2044 

 0.2031 



-I-0.0019 

 -j-0.0019 



— 0.0006 

 — 0.0006 



35.3805 

 35.3827 



III. 2038 

 III. 2025 



D. 



