824 
Notes. 
adjustments to secure its parallelism and proper tension ; the 
thickness of the section is regulated by a screw of fifty threads 
to the inch, reading to thousandths by means of a micrometer 
head ; the feed is either automatic by means of a cup, in which 
a suitable quantity of shot can be placed, acting by gravitation 
on a lever ; or, as Dr. Matthews prefers, is capable of being 
regulated by hand. Owing to the steady motion of the saw 
when in proper adjustment sections of suitable tissues can be 
cut as thin as the thousandth of an inch ; the surfaces show no 
trace of the saw cut, and are almost polished ; very little after 
treatment is needed to remove the few scratches left by the saw, 
and if required for mounting in balsam it can be done at once, 
taking the usual precautions to prevent penetration, and the 
consequent obliteration of structure. The machine has been 
constructed with his usual care by Mr. J. W. Bailey. 
Some interesting experiments on “Brownian Movements” 
have been communicated to the Royal Microscopical Society, 
by Wm. M. Ord, M.D. The paper, which does not admit of 
profitable abbreviation, will be found in vol. ii. of the Society’s 
Transactions, p. 656. 
The Royal Institution Christmas Lectures, adapted to a juve- 
nile auditory, will this year be given by Professor Tyndall, the 
subject being “Water and Air.” As full a report as possible 
will be given in the “Journal of Science.” 
