









98 NOBERT’S TEST PLATE 
253, states that with monochromatic light, and Powella 
Lealand’s 35, =, and 5 objectives, a Hartnack immersion, | 
No. 11, and a Wales 3, with amplifier, he satisfactorily 
resolved the 29th and 30th bands of Nobert’s test plate. 
a letter to the writer written since, Dr. Woodward infor 
me that the plate used was the same one used by Sulliv 
and Wormley, as the 30th band was the finest on that; 
result did not show that finer lines could not be seen. Dr 
Woodward informs me, that, since writing that paper, he! 3 
received a Nobert plate with the nineteen bands, and that 
covering glass was too thick for the J; objective, but 
Dr. Woodward has sent to me a photograph of the 16 
17th, 18th, and 19th bands, taken by Dr. Curtis with 
Powell and Leland 3. In the photograph, the lines of 
16th and 17th bands may be counted with some difficl 
but if the whole band is copied, or if the bands are of 
width of zvo of an inch, there are not lines enough. 
lines of the 18th and 19th bands cannot be counted in 
photograph. From this it will be noticed that Dr. Wo 
ward has resolved finer lines than any other observer 
yet seen, so far as report gives us any information. 
_ My esteemed correspondent, M. Th. Eulenstien, of § 
gard, Wirtemberg, writes to me, under date of Dee. 1 
1867, “I have myself resolved the 14th band with a tz P 
ell and Lealand, and also, but less unmistakably, with 4 
11 Hartnack’s immersion, with oblique light.” “Nol 
himself has never seen with his highest powers higher 
the 14th.” “This will show you the continental state 
affairs.” Mr. R. C. Greenleaf and myself have lately * 
several objectives, and the result is appended below:* — 
Barta’ inmerion No bath ag op nee wee ee 
brian ky ks OS Lae yy ak ee ann aes ee rep E E E, 
