Am.  Jour.  Pharm.  ) 
January,  1921.  J 
An  Epoch-Making  Discovery. 
2  9 
are  not  absolute  quantities,  as  has  always  been  hitherto  assumed  in 
physics,  but  it  is  declared  that  they  actually  have  different  values 
for  different  systems  of  reference  moving  with  relation  to  one 
another. 
Newton  had  established  concepts  of  what  it  has  been  customary 
to  call  "Absolute  true  and  mathematical  time"  and  "absolute 
space." 
Experiments  of  certain  physicists  had  proved  man's  inability  to 
detect  absolute  motion  (motion  with  respect  to  the  hypothetical 
aether).  This  has  recently  led  to  the  development  of  a  theorem 
to  the  effect  that  "all  laws  of  physical  nature  should  have  been 
formulated  with  reference  to  a  definite  coordinate  system,  are  valid, 
in  precisely  the  same  form  when  referred  to  another  coordinate 
system  which  is  in  uniform  rectilinear  motion  with  respect  to  the 
first." 
This  empirical  law  is  Einstein's  "Special  Theory  of  Rela- 
tivity." 
It  is  a  simple  matter  to  make  time  duration  calculations  with  a 
clock  situated  where  the  event  is  taking  place.  It  is  more  difficult 
to  make  such  calculations  with  events  happening  at  two  different 
places,  for  then  some  elaborate  precautions  must  be  taken  to  bring 
the  two  clocks  into  synchronous  agreement.  W  nen  we  come  to 
deal  with  calculations  where  the  clocks  are  not  at  rest  with  reference 
to  each  other,  as  for  instance,  when  one  is  on  a  railway  train  travel- 
ing at  a  high  rate  of  speed,  all  ordinary  methods  of  measurement 
and  comparison  fail. 
Such  refinements  of  observation  seem  to  be  beyond  our  con- 
ceptions of  practicality  and  yet  we  are  assured  of  their  value  by 
those  who  deal  with  calculations  involving  the  physical  laws,  par- 
ticularly with  reference  to  light. 
One  of  the  modern  concepts,  which  is  at  variance  with  New- 
tonian principles,  is  the  declaration  that  a  gravitational  field  has  an 
influence  upon  a  ray  of  light.  Einstein  asserted  his  ability  to  prove 
this  by  the  application  of  his  method  to  observations  and  calcula- 
tions of  certain  astronomical  phenomena.  This  assertion  is  said  to 
have  been  confirmed  by  observations  of  the  photographic  registra- 
tions of  stars  during  the  eclipse  of  the  sun  in  May,  19 19,  and  afford 
justification  for  the  hope  that  some  of  the  obscure  laws  of  nature 
may  be  fathomed  by  a  further  pursuit  of  this  subject  by  those 
