434      CULTURE  OF  COCHINEAL  IN  THE  CANARY  ISLANDS. 
an  atmosphere  of  carbonic  acid,  when  treated  in  the  same  man- 
ner, caused  a  dense  precipitate  of  carbonate  of  baryta  ;  so  that 
the  charcoal  does  not  prevent  the  abstraction  by  water  of  the 
carbonic  acid,  as  is  the  case  with  iodine. 
If  there  were  any  grounds  for  the  objection  raised,  the  second 
experiment  should  have  shown  at  least  an  excess  of  carbonate  of 
baryta  over  the  first,  for,  according  to  Scharling,  "a  man  weigh- 
ing 170  lbs.  gives  off  from  the  lungs,  in  the  course  of  one  hour, 
33-5  grammes  (more  than  five  hundred  grains)  weight  of  this 
gas,"  consequently  a  considerable  volume  must  have  passed 
through  the  charcoal  employed.  That  the  reverse  is  the  case  is 
doubtless  due  simply  to  the  somewhat  larger  amount  of  alkaline 
carbonates  contained  in  the  first  portion  of  charcoal. — Ibid. 
CULTURE  OF  COCHINEAL  IN  THE  CANARY  ISLANDS. 
By  Dr.  Theodor  E.  Martitjs. 
This  costly  coloring  material,  which  was  formerly  obtained 
solely  from  Mexico,  has,  during  the  last  thirty  years,  become  an 
object  of  artificial  culture.  This  has  given  rise  to  the  introduc- 
tion into  commerce  of  cochineal  from  Teneriffe,  Algeria,  and  it  is 
probable  that  it  will  soon  be  obtained  from  the  East  Indies. 
The  accounts  of  the  collection  and  preparation  of  cochineal 
are  at  present  very  contradictory,  and  the  circumstance  that 
black  and  silver  cochineal  are  met  with,  has  especially  given  rise 
to  very  discrepant  views. 
During  the  last  two  years  Teneriffe  cochineal  has  come  into 
considerable  competition  with  Honduras  cochineal,  and  it  would 
appear  from  the  following  statements  more  correct  to  consider 
this  kind  of  cochineal  as  the  produce  of  the  Canaries.  In  a  very 
interesting  work  by  Dr.  Julius  Freiheron  von  Minutoli,*  it  is 
shown  that  in  the  year  1853  the  culture  of  cochineal  was  carried 
on  in  the  following  of  the  seven  inhabited  Canary  Islands  : — 
1.  Teneriffe  The  author  states  that  the  niguera  ehucaba 
or  tun  era  grows  remarkably  well  on  this  island. 
2.  Fuerteventura  likewise  appears  to  be  situated  very 
favorably  for  the  culture  of  nopal. 
*  El  Pasado  y  Provenir  de  las  Islas  Canarias.    Berlin,  1854. 
