Entry into Inner S pace
163
!
"
.
Ultimately, a limit to the depth of divescan be seen in the purely
physical effects of the sea’s pressure on the breathing mixtures. As
the pressure increases, the gases become thicker and more difcult
‘
to breathe; Apart from the greater effort needed to moyethe gases
:
in and out of the lung”s, the reduction in ventilation of the lung3may
‘
allow… carbon dioxide to raccumu1ate particularly during heavy work.
Normally the level of carbon dioxide «in the…lungs, and theref0re in
the arteries, remains nearly constant, but once it begins to build up,
the situation deteriorates rapidly becauSe the concentration
carbon dioxide in theblOdd acts as a ‘:trigge for.respiration. Apart
from the'danger in an unsuccessful stimulation :ofthe already over—
{
loaded respiratory system, the carbon- dioXideenhances the narcotic
effects of the 'inert gases._ The solution to this respiratory resistance
is to use less viscous and: less dense gases than those in the air.
Helium, the most widely used, is as dense at 13000 feetasis nitrogen
100 feet—But at 800 » feet thereis some evidence that even With
helium the resistance to breathing detectably limits “work or exercise
°
Experiments have, therefore, been made, replading the ,helium by
hyd‘rbgen, the lightest…known
Nevertheless, in spite of such
diiculties, pioneers;. Such:as Dr
Link, ; Dr George F.
Bond and Jacques—Yves Cousteau have gone on record as predicting
dives to 3,000
ofus.
-î
-.
'
‘
'
In the lastthirty‘ years of so,, the ,depths of experimental dives
have already been pushed from3oo t0 1,000 feet Dr N. C. Flemming
of the British National Institute of =Oceanography has summarized
the more importantdevelopments ‘As early as ;16 50 divers c0uld
-
work-for up to—one hour at 100 feet «and “progress up to…1900Was
restricted to some extremely important advances in equipment,
safety and comfort.
By
experimental
outside the normal
made, to i‘3001feet-for
'
one hour.
.
,. ; Between
of Short experimental
,
dives by… the Royal «NawadfDï Hannes i_»Keller,«independently
.
«depth record rst to
…dives in” the
These diVes, all carried Out with only one or
two men, “usually
some degree of bends, and nally
caused ionelfaœlity. ;The
“demonstrated thatmèn could sùrvive
èof1up to 30
but eàlsd shéwed, that…açmore
caritious ,—a.ppr0ach WashèCèssar'y.’ _ _—;ÿ
V
“
'
.
à
mdrè‘to Zdecompress-after a dive
of“ ve
-
minutes ;‘at
feet;wthe‘«V01umeS —0f ’
breathing mixture
163
!
"
.
Ultimately, a limit to the depth of divescan be seen in the purely
physical effects of the sea’s pressure on the breathing mixtures. As
the pressure increases, the gases become thicker and more difcult
‘
to breathe; Apart from the greater effort needed to moyethe gases
:
in and out of the lung”s, the reduction in ventilation of the lung3may
‘
allow… carbon dioxide to raccumu1ate particularly during heavy work.
Normally the level of carbon dioxide «in the…lungs, and theref0re in
the arteries, remains nearly constant, but once it begins to build up,
the situation deteriorates rapidly becauSe the concentration
carbon dioxide in theblOdd acts as a ‘:trigge for.respiration. Apart
from the'danger in an unsuccessful stimulation :ofthe already over—
{
loaded respiratory system, the carbon- dioXideenhances the narcotic
effects of the 'inert gases._ The solution to this respiratory resistance
is to use less viscous and: less dense gases than those in the air.
Helium, the most widely used, is as dense at 13000 feetasis nitrogen
100 feet—But at 800 » feet thereis some evidence that even With
helium the resistance to breathing detectably limits “work or exercise
°
Experiments have, therefore, been made, replading the ,helium by
hyd‘rbgen, the lightest…known
Nevertheless, in spite of such
diiculties, pioneers;. Such:as Dr
Link, ; Dr George F.
Bond and Jacques—Yves Cousteau have gone on record as predicting
dives to 3,000
ofus.
-î
-.
'
‘
'
In the lastthirty‘ years of so,, the ,depths of experimental dives
have already been pushed from3oo t0 1,000 feet Dr N. C. Flemming
of the British National Institute of =Oceanography has summarized
the more importantdevelopments ‘As early as ;16 50 divers c0uld
-
work-for up to—one hour at 100 feet «and “progress up to…1900Was
restricted to some extremely important advances in equipment,
safety and comfort.
By
experimental
outside the normal
made, to i‘3001feet-for
'
one hour.
.
,. ; Between
of Short experimental
,
dives by… the Royal «NawadfDï Hannes i_»Keller,«independently
.
«depth record rst to
…dives in” the
These diVes, all carried Out with only one or
two men, “usually
some degree of bends, and nally
caused ionelfaœlity. ;The
“demonstrated thatmèn could sùrvive
èof1up to 30
but eàlsd shéwed, that…açmore
caritious ,—a.ppr0ach WashèCèssar'y.’ _ _—;ÿ
V
“
'
.
à
mdrè‘to Zdecompress-after a dive
of“ ve
-
minutes ;‘at
feet;wthe‘«V01umeS —0f ’
breathing mixture