Beck^ on a Revolving Disc-holder, 
101 
As a plea for the poverty of the figures,, I had nothing at 
hand but very old paper to print on. The day of taking the 
negatives was most tantalising — sunshine by fits^ with a pleni- 
tude of rain, and those fits only of a few seconds' duration. 
In fact, everything had to be tempered with much patience. 
The apparatus, extemporised for the purpose, had its defects ; 
the small plates were, by a modified " dry process,^' prepared 
for other purposes. Of the eight taken, enclosed are figures 
from six ; the other two — one of a crushed insect, and a repeti- 
tion of the plate with two insects — I do not send. 
Bearing on the subject of life in strange places and curious 
conditions, and enjoying what we deem poisons, is a short 
remark in the 3rd number of the ' Popular Science Review' 
for this month — Mr. Attfield having found Acari nourishing 
themselves on an extract of nux vomica, and even feasting on 
strychnine. In the article Acarus Microscopic Dictionary') 
I cannot find among the described species any that exactly 
correspond with these. The projection or tubercle, at the end 
of the body, is named in the Acarus hippopodos, found on the 
ulcer crusts of horses' legs but the curious pouch-groove I do 
not see noticed. If new, perhaps you may venture to be 
sponsor, for I feel too uncertain about the baptismal registry 
of others to propose a name. The microscope used for the 
observations was Smith, Beck, and Beck's, with objectives 
two-third and one-fifth ; for the photographs, their one-fifth, 
and an acromatic of lower power of my own making. The mi- 
cro-camera was put together with Abraham's achromatic prism 
for a mirror, a Coddington lens (which, by the way, was 
fractured across the groove entirely through the glass) as a 
condenser, and a small pocket camera for the sensitive dry- 
plate. Therefore, you will please not criticise the prints, as 
they are but rude specimens, and not examples, of what can 
be done with care in photo-micrography. 
A Revolving Disc-holder for Opaque Objects. 
By Richard Beck. 
This piece of apparatus is designed to facilitate the ex- 
amination of objects when under Lieberkuhn illumination. The 
forceps which are most frequently used under such circum- 
stances are very limited in many of the requiisite move- 
