Monthly Microscoplcan 
Journal, Dec. 1, 1869. J 
Boyal Microscoj)ical Society. 
293 
obtained by tbe immersion -^^ih. of Messrs. Powell and Lealand ; 
and I may here say, that on a thorough comparison of this objective 
with the dry gV^h and aVth of the same makers, I found that not 
merely did their new lens resolve higher bands on the Nobert's 
plate than could be made out with the sVth and gVth, but that it 
would bear the use of eye-pieces and amphfiers so as to give higher 
powers than can be obtained with the Ath, with much better 
illumination, with better definition, as well as with a practical 
working distance. The lens may therefore be especially commended 
for anatomical work when the highest powers are desirable. 
In conclusion, I desire to remark on two points contained in the 
very interesting paper on " Immersion Objectives and Test-objects " 
by Mr. John Mayall, jun.* 
1st. Mr. Mayall says : — " Dr. Woodward seems not to have 
been sure of the accuracy of the count he made on his photograph ; 
for although in one part of his paper in the current (October) 
number of the Journal of this Society, he says the photograph 
shows the twelfth band as resolved into thirty-seven Hues, farther 
on he says that forty is the real number in that band." This mis- 
apprehension on the part of Mr. Mayall arose from a misprint in 
the Journal.t On p. 231, fourteenth line, " 12th band " reads 
in my original MS. "13th band;" on the thirtieth line of the 
same page, I find "12th band" printed instead of "19th band," 
which is the reading of the original. The same article contains 
some other singular misprints, most conspicuous among which may 
be mentioned, " Starting's work on the microscope," p. 225, instead 
of Harting's ; and " Greenhap," p. 228, instead of Grreenleaf. At 
the time my article was prepared, I had no doubt whatever of the 
true number of lines in all the bands resolved, except the fifteenth, 
about which, as I stated, I was uncertain whether the true number 
of lines was forty-five or forty- six. At present, additional work 
has satisfied me that forty-five is the number, and I am also well 
assured of the correct number as given above for the remaining 
bands. I freely admit that the difiiculty of determining which is 
the last real, and which the first spectral line is very great even on 
glass positives ; nevertheless, a comparison of several photographs 
with each other, and with the bands as seen in the microscope, has 
satisfied me that my count is correct. 
The second point in Mr. May all's paper to which I desire to 
refer is the following remark : — " Dr. Woodward's photographs 
support an opinion given by Mr. Wenham many years ago, that 
the time would come when photography would reveal minute detail 
much more palpably than it can be seen in the microscope." If by 
this Mr. Mayall means that he has not been able to see the lines 
* 'Monthly Microscopical Journal,' February 1, 1869, p. 90, 
t * Quarterly Journal of Microscopical Science,' October, 1808. 
