686 



Transactions of the Society. 



No. 8. Powell and Leland 

 stage micrometer on 

 glass, similar sub-divi- 

 sions ; same instru- 

 ments. 



1 div. = 0-169 fi 



No. 9. Glass micrometer 

 by the late Charles 

 Fasoldt. Same instru- 

 ments as above (1 div. 

 = 0'169/u) used in first 

 series. Bulloch stand 

 No. 2, Bausch and 

 Lomb filar, and A A 

 Zeiss objective (1 div. 

 = 0-369 m) used in 

 second series. 



No. 10. Beck stage micro- 

 meter on glass, divided 

 into hundredths and 

 thousandths of an inch. 

 Spencer stand, Zeiss 

 filar, and Leitz No. 2 

 objective. 



1 div. = 0-302^ 



No. 11. Beck stage micro- 

 meter on glass, divided 

 into tenths and hun- 

 dredths mm. Spencer 

 stand, Zeiss filar, and 

 Leitz No. 3 objective. 

 1 div. = 0-169 n 



No.IIa. Beck stage micro- 

 meter on glass ; same 

 instruments except 

 Leitz No. 2 objective. 

 1 div. = 0-302 ,u 



No. 12. Tolles stage 

 micrometer on glass, di- 

 vided into hundredths, 

 thousandths, and half- 

 thousandths of an inch ; 

 same instruments as in 

 No. 11a. 



1 div. = 0-302 M 





,'„ mm. 

 1st 

 2nd 

 3rd 

 4th 

 5th 



No. of 

 Div. of 

 Micro- 

 meter. 



Mean 



1st 

 2nd 

 3rd 

 4th 

 5th 

 6th 

 7th 

 8th 

 9th 

 10th 



rea in- 

 1st 

 2nd 

 3rd 

 4th 

 5th 



576' 



585' 

 582' 



582-2 



Mean 



& mm. 

 1st 

 2nd 

 3rd 

 4th 

 5th 



842-8 

 843-8 

 838-3 

 844-9 

 846-1 



843-2 



577' 

 578- 

 583' 

 581' 

 586' 



Mean 



rso in- 



1st 



2nd 

 3rd 

 4th 

 5th 



Mean 



1st 



2nd 



3rd 



4th 



5th 



581-4 



849-3 

 842-1 

 835-4 

 843-3 

 847-6 



843-5 



Mean 



840-3 

 839-5 



838-7 

 844-8 

 841-9 



div. 

 578v 

 588-0 



841-0 



Remarks. 



Record Book, page 10. 

 Total length not 

 determined. 



Record Book, pages 

 5, 17. 



These corrections re- 

 present the mean 

 of two series of 

 measurements; 

 twenty micrometer 

 readings on each 

 space in each series. 



Record Book, page 3. 

 Total length not 

 determined. 



Record Book, page 30. 



Lines deteriorated. 

 Total length not 

 determined. Ten 

 readings on each 

 space (five on each 

 end). 



Record Book, page 30. 



Ruled on same slide 

 as No. 11. Lines 

 deteriorated. Total 

 length not deter- 

 mined. Ten read- 

 ings on each space. 



Record Book, pages 



30, 31. 

 Total length not 

 * determined. Lines 



deteriorated. Ten 



readings on each 



space. 



