July.  24,  1902. 
JOURNAL  OF  HORTICULTURE  AND  COT l'ACE  GARDENER. 
83 
be  rotated.  The  upper  portion  is  provided  with  a  ledge  at 
bottom,  and  a  sliding  fitting  at  the  top,  with  springs  for  clamp¬ 
ing  the  objects  firm  to  the  stage.  It  has  also  a  socket  at  the 
corner  for  holding  the  forceps  when  in  use. 
Immediately  under  the  stage  is  a  grooved  fitting  with  pinion 
and  milled  heads  for  carrying  the  sub-stage,  and  cylindrical 
fittings  to  receive  all  kinds  of  illuminating  apparatus  which  are 
required  below  the  stage.  The  stem  tube  is  fixed  to  the  lower 
part  of  the  main  limb  for  carrying  the  mirror  and  white  cloud 
illuminator.  This  is  the  lengthening  arm  to  mirror  for  giving 
oblique  side  illumination,  and  this  the  semi-circle  in  which  the 
mirror  swings.  When  using  artificial  light,  it  is  very  desirable 
to  have  a  proper  lamp  that  can  easily  be  adjusted  to  various 
heights  to  suit  transparent  or  opaque  objects.  This  is  one  of 
Messrs.  Becks,  and  is  a  very  useful  one;  the  shade  intercepts 
the  glaring  light  from  the  eyes  of  the  observer. 
For  high  power  objectives  that  cannot  be  advantageously 
used  with  Lieberkuhuns  for  opaque  objects,  Messrs.  Beck  have 
invented  this  patent  illuminator,  into  which  they  have  introduced 
a  disc  of  thin  glass  attached  to  a  milled  head,  and  by  rotating 
the  same,  any  angle  of  light  can  be  exactly  adjusted.  This 
appliance  is  introduced  by  a  slot  into  the  interior  of  an  adapter 
between  the  objective  and  the  nose-piece  of  the  microscope. 
The  light  enters  through  the  aperture,  and  is  reflected  down¬ 
wards  to  the  object  beneath. 
The  camera  lucida  is  a  very  useful  appliance.  The  eye-piece 
of  the  microscope  should  be  placed  at  an  elevation  of  ten  inches 
from  the  table,  the  object  on  the  stage  being  properly  focussed. 
The  eye  shade  is  removed  and  the  camera  slipped  on  in  its  place. 
A  piece  of  white  paper  is  then  put  on  the  table,  and  the  iris  of 
the  eye  should  be  in  a  position  to  see  through  the  prism  and  also 
on  to  the  paper.  The  result  will  be  that  the  object  under 
ZNJJI  '1 A  Placid  Effect  in  Garden  Design.  See  page  78.) 
There  are  several  methods  of  condensing  the  light  and 
throwing  it  more  intensely  from  the  lamp  to  the  object  under 
observation.  Here  is  the  bull’s-eye  condenser,  one  that  is  mostly 
used  for  concentrating  the  light  from  the  mirror  to  the  object 
on  the  stage.  This  is  the  small  condensing  lens  for  fitting  on 
to  the  main  limb  of  the  instrument  for  the  illumination  of  opaque 
or  other  objects  from  above,  and  the  blue  glass  moderator  is  used 
to  tone  down  the  glare  when  too  intense  for  the  eyes.  The 
silver  side  reflector  is  used  with  the  bull’s-eye,  one  on  each  side 
of  the  instrument,  to  reflect  the  light  on  both  sides  of  subjects 
that  are  of  an  uneven  nature,  such  as  minerals,  mounted  as 
opaque  objects,  otherwise  one  side  would  be  illuminated  and 
the  other  side  would  be  in  the  shade.  The  parabolic  Lieber- 
kuhun  is  used  for  a  similar  purpose  ;  it  slides  on  to  the  objec¬ 
tives.  The  ordinary  Lieberkuhuns  also  slide  on  to  the  objectives 
in  the  same  way,  but  they  reflect  the  light  direct  on  to  the 
object  from  above;  and  should  the  object  be  too  transparent, 
then  by  fixing  the  dark  wells  in  the  sub-stage  it  will  be  seen 
on  a  beautiful  dark  ground. 
observation  will  be  reflected  through  the  camera  to  the  paper 
below,  and  can  thus  be  clearly  defined,  traced  or  drawn  by 
following  the  reflections.  Thus  minute  objects  can  be  drawn  that 
could  not  otherwise  be  obtained. 
(To  be  continued.) 
- - - - 
The  Moon  and  ^Thunderstorms. 
A  connection  between  thunderstorms  and  the  moon’s  phases  is 
now  claimed  by  meteorologists.  Some  months  ago  a  greater 
frequency  of  such  storms  at  new  moon  than  at  full  moon  was 
noticed  in  the  records  at  Greenwich  for  thirteen  years,  and  from 
other  inquiry  it  appears  that  Madrid  observations  for  twent\ 
years  give  similar  evidence.  The  Spanish  records  show  29  per 
cent,  of  the  thunderstorms  near  new  moon.  22.8  near  first  quarter, 
21.8  near  full  moon,  and  26.4  near  last  quarter. 
