SCIENTIFIC SUMMARY. 
221 
is not sent to us among the other journals, British and foreign, which 
we receive. Dr. Woodward says : — IC I may mention here, as a matter of 
interest, that I have recently examined two new test-plates by Nobert — the 
first ruled for Professor Barnard, of Columbia College ; the second for the 
Army Medical Museum — in which the maker has attempted to rule lines 
twice as fine as those of the nineteenth band. These plates have twenty 
bands. The first ten correspond respectively tQ the 1st, 3rd, 5th, 7th, 9th, 
11th, 13th, 17th, and 19th of the old plate. The lines in the second group 
of ten bands purport to be ruled at the following distances apart : — The 
11th band of a Paris line, the 12th band jabbo* an( ^ 80 on ll P f° the 
20th band, lines of which are said to be aoibo a P ai 'i s ^ ne ap^rt. As I 
have not yet been able to resolve any of these new bands, I will not at pre- 
sent express an opinion as to whether Nobert has actually succeeded in 
ruling them as attempted.” 
Papers of the Quarter on Microscopical Subjects.— The following have been 
published in the a Monthly Microscopical Journal ” for January, February, 
and March, and some, especially those of Mr. Ballinger, are of great im- 
portance : — 
Notes on so-called Acarellus. By S. J. Mclntire, F.R.M.S. — Further 
Researches into the Life History of the Monads. By W. II. Bal- 
linger, F.R.M.S., and J. Drysdale, M.B. — On the Microscopic Struc- 
ture of a Granitoid Quartz-porphyry from Galway. By Professor 
Edward FIull, M.A., F.R.S. — The Structure of the Scales of Lepisma 
Saccharina. By G. W. Morehouse. — On the Origin and Development 
of the Coloured Blood Corpuscles in Man. By Dr. H. B. Schmidt, 
New Orleans. — Further Researches into the Life History of the 
Monads. By W. H. Ballinger, F.R.M.S., and J. Drysdale, M.D. — 
On a Simple Method of Preparing Lecture-Illustrations of Microscopic 
Objects. By Rev. W. H. Ballinger, F.R.M.S. — A Method of Dissect- 
ing Podura Scales. By F. H. Wenham, V.P.R.M.S. — The President’s 
Address. — Further Researches into the Life History of the Monads. 
By W. H. Dallinger, F.R.M.S., and J. Drysdale, M.B. — Further Notes 
on the Zoosperms of Crustacea and other Invertebrata. By Alfred 
Sanders, Lecturer on Comparative Anatomy at the London Hospital 
Medical College. — Angular Aperture of Object-glasses. By F. H. 
Wenham, Vice-President R.M.S. — Further Remarks on Immersion 
Apertures. By J. J. Woodward, Assistant-Surgeon U.S. Navy. 
PHYSICS. 
A New Form of Maximum and Minimum Thermometer was some time 
since described in a French scientific journal. It is formed of a compound 
spiral, consisting of two differently expansible metals electroplated. By 
increase of temperature it tends to unroll, by decrease to twist up • in so 
doing it moves one or the other of a pair of indices over a graduated scale, 
the one of which registers the highest temperature attained, the other the 
lowest. If required, a third needle may be added, by means of which the 
