612  JSotices  respecting  New  Books. 
This  want  is  now  supplied  by  Mr.  Baly's  excellent  work,  which 
forms  one  of  the  series  of  Text- Books  of  Physical  Chemistry 
now  being  issued  by  Messrs.  Longmans,  under  the  general 
editorship  of  Sir  W.  Eamsay.  After  an  historical  introduction 
devoted  to  an  account  of  the  rise  and  progress  of  spectroscopy, 
the  author  deals  with  the  slit,  prisms,  and  lenses,  and  their  combi- 
nation to  form  a  complete  prism- spectroscope.  The  practical  use 
of  this  instrument  is  then  fully  dealt  with.  The  diffraction-grating 
and  its  practical  use  are  next  considered.  Then  follow  chapters 
dealing  with  measurements  in  the  infra-red  and  ultra-violet 
regions,  with  the  application  of  interference  methods  to  spectro- 
scopy, the  efficiency  of  the  spectroscope,  the  photography  of  the 
spectrum,  the  production  and  nature  of  spectra,  the  Zeeman 
effect,  series  of  lines  in  spectra,  and  change  of  wave-length  by 
pressure  and  by  motion  in  the  line  of  sight.  An  interesting 
feature  of  the  book  is  the  detailed  and  fully  illustrated  description 
of  Eowland's  grating  ruling-engines  given  in  the  concluding- 
chapter.  The  Appendix  contains  recipes  for  silvering-solutions 
for  glass  mirrors.  An  index  of  names  and  subjects  is  provided  at 
the  end  of  the  book.  In  spite  of  the  vast  amount  of  matter  dealt 
with,  most  of  the  explanations  given  are  characterized  by  clearness, 
and  the  book  contains  many  valuable  practical  hints  which  are  the 
result  of  the  author's  own  experience,  and  for  which  the  reader 
will  feel  duly  grateful.  There  are  a  number  of  obvious  misprints 
— which  is  almost  inevitable — and  occasionally  there  are  lapses 
from  that  clearness  which  characterizes  the  book  as  a  whole.  We 
w'ould  particularly  direct  the  author's  attention  to  the  entirely 
inadequate  if  not  actually  misleading  account  of  the  principle  of 
Langley's  bolometer  given  on  p.  229,  which  should  be  thoroughly 
revised  in  the  next  edition. 
The  Science  Year-Boole.  With  Astronomical,  Physical  &  Chemical 
Tables,  Summaries  of  Progress  in  Science,  Directory  and  Diary 
for  1906.  Edited  by  Major  B.  P.  S.  Badef-Powell.  London  : 
King,  Sell  &  Olding,  Limited.    1906.     Pp.  208  +  365  +  27  +  vi. 
The  scope  of  this  most  useful  year-book,  which  is  in  its  second 
annual  issue,  is  sufficiently  described  by  its  title.  Compressed 
within  the  first  208  pages  is  a  vast  amount  of  information, 
including  brief  summaries  of  scientific  progress  during  the  past 
year.  Then  follows  a  diary,  with  a  whole  page  for  every  day  of 
the  year.  A  few  additional  pages  for  memoranda  &c.  follow,  and 
finally  an  index  is  provided. 
It  was  hardly  to  be  expected  that  a  publication  of  this  kind 
should  be  quite  free  from  error.  We  note,  for  example,  that 
Prof.  Unwin's  name  is  still  given  as  that  of  the  Professor  of 
Engineering  at  the  Central  Technical  College ;  a  number  of 
misprints  are  almost  unavoidable — but  these  are  small  blemishes, 
and  do  not  seriously  mar  the  extreme  usefulness  of  the  book  as 
a  whole. 
