The Microscope. 



185 



limits of personal and instrumental error, according to the high- 

 est living authority upon this subject, who writes in substance, 

 that it is easy to measure 1-50,000 inch, but to be sure of 1-100,000 

 inch, is not possible. 



Date. 



Date. 



x 



C5 J3 



t. o 



CD cs 



> 9> 



CD io 



M 

 CS £ 



> CD 

 <! 



1885. 

 June 24 



9 p. m. 

 June 2.5 



8 30 p. m. 

 June 26 



8 p.m. 

 June 27 



7 40 p.m. 

 June 27 



8 55 p m. 

 June 28 



8 05 p. m. 

 June 29 



7 20 p. m. 

 June 29 



8 20 p. m. 

 June 30 



9 p. m. 

 July 2 



8 25 p, m. 

 July 3 



9 15 p. m. 

 July 2 



9 45 p. m. 

 July 7 



8 p. m. 



1885. 

 July 7 



8 45 p. m. 

 July 7 



9 35 p.m. 

 July " 



10 10 p. m. 

 July 9 



8 p. m. 

 July 9 



3 40 p.m. 

 July 9 



9 15 p. m. 

 July 9 



10 p. m. 

 July 11 



7 20 p. m. 

 July 11 



7 53 p. m. 

 July 11 



8 37 p. m. 

 July 11 



9 36 p. m. 

 July 17 



7 45 p. m 

 July 17 



8 40 p. m. 



207 

 273 

 2S4 

 275 

 278 

 198 

 274 

 278 

 255 

 285 

 288 

 986 

 269 



861 



380 

 345 

 361 

 350 

 393 

 389 

 348 

 363 

 358 

 356 

 349 

 351 



(14)312 

 (15)315 

 (16)313 

 (17)315 

 (18)312 

 (19)317 

 (20)322 

 ,21)318 

 (22)307 

 (23)318 

 (24)328 

 (25)314 

 (26)312 



( 7)313 

 ( 8)314 

 ( 9)313 

 (10)319 

 (11)313 

 (12)323 

 (13)313 



( 5)313 



( 6)313 



( 7)319 



( 8)318 



Average of each 100 : 



200: 



June 27, 7:40 p, m., 



" 29,8:30 p, m... 

 July 2, 9:45 p, m„. 



" 7,10:10 p.m.,. 



" 9, 40 p. m 



" 11, 9:36 p. m., . 

 June 29, 3:20 p, m., 

 Jnly7, 10:'0p. m„. 



•' 11,9:36 p.m.,.. 



.( 1)322. 

 .( 2)324. 

 ( 3,321. 

 .( 4)315. 

 ..( 5)316. 

 .( 6)318. 

 .( 1)323. 

 .( 2)318. 

 .( 3)317. 



Average of whole number (650) 0003186 inch 



Correction for excess of value of micrometer 0000023 



.0003163=1-3162 inch. 



Smallest corpuscle of the whole number 000198=1-5050 



Largest corpuscle of the whole number 000393=1-2544 " 



The conclusion to be deduced from the above figures, is 

 obviously that when a sufficient number of corpuscles are meas- 

 ured, there appears to be an average size which varies within 

 very narrow limits, which may possibly be accounted for or at 

 least is consistent with personal and instrumental errors ; for 

 though I have carried out the figures to the sixth decimal place, 

 I have not the presumption to declare that the result can be re- 

 lied upon farther than the fifth place, and have carried out the 

 figures to the sixth, only to insure accuracy in the fifth so far as 



