Am'sS^*iSh7arm'}       Olive  Oil  and  its  Adulterations.  437 
mate  decides  the  question  of  hardiness,  so  that  when  a  seedling  grape 
is  announced  as  being  perfectly  hardy  and  exempt  from  rot  in  the 
berry,  it  may  be  true  as  far  as  hardiness  is  concerned,  in  the  climate 
where  it  originated,  if  it  happened  to  be  a  specially  good  climate,  but 
it  does  not  follow  that  it  would  be  hardy  in  other  parts  of  the  coun- 
try, as  hundreds  who  have  purchased  such  plants  can  abundantly 
testify. 
Another  form  of  mildew  that  may  sometimes  be  seen  on  grape- 
leaves  is  a  species  of  Erysiphe.  This  form  appears  on  the  upper  sur- 
face of  the  leaves,  also  on  the  surface  of  the  fruit,  its  appearance  be- 
ing somewhat  similar  to  a  dusting  of  fine  flour,  and  may  be  brushed 
off  without  leaving  any  apparent  marks  of  injury,  but  its  effects  are  to- 
retard  growTth.  Young,  green  shoots  once  covered  with  this  fungus 
cease  to  grow,  and  will  remain  green  until  the  frosts  of  winter  destroy 
them.  When  the  fruit  becomes  severely  attacked  it  cracks  open,  and 
the  seeds  will  protrude.  Green  shoots  will  also  crack  if  the  mildew 
attacks  them  severely.  Unlike  the  peronospora  it  abounds  mostly  in 
the  early  part  of  the  growing  season.  Sudden  changes  of  the  weather 
from  heat  to  cold  will  produce  it,  but  our  native  grapes  do  not  suffer 
materially  at  any  time  from  this  kind  of  mildew. 
OLIVE  OIL  AND  ITS  ADULTERATIONS. 
By  John  Franklin  Hildebeand,  Ph.G. 
The  author's  thesis  contains  the  following  survey  of  various  tests 
recommended  in  connection  wTith  olive  oil,  without  giving  special  ex- 
perimental results.  Olive  oil  is  a  nearly  inodorous,  pale  greenish- 
yellow,  unctuous  fluid,  with  a  purely  oleaginous  taste,  peculiarly  grate- 
ful to  those  who  relish  oil.  It  does  not  suffer  active  decomposition  at 
a  temperature  not  exceeding  600°  F,  and  wThen  cooled  to  below  32° 
F.  it  congeals  into  a  granular  solid  mass.  It  is  very  slightly  solu- 
ble in  alcohol,  but  its  solubility  is  increased  by  admixture  with 
castor  oil.  It  is  soluble  in  1 J  parts  of  ether.  When  pure  it  has  little 
tendency  to  become  rancid.  Specific  gravity  varies  from  about  *914- 
•918  at  60°  F.  Olive  oil,  being,  with  the  exception  of  almond  oil, 
the  most  costly  of  the  fixed  oils  of  commerce,  is  consequently  subject 
to  adulterations.  Nut,  poppy,  rape,  lard  and  cotton-seed  oils  are  com- 
mon adulterants.    Refined  tallow-olein,  is  said  to  have  been  used  in 
