Glass J tube formed from 1mm bore thick walled capillary tube, with a brass screw and
collar at the end of the longer limb. Used for sampling small quantities of gas held over water (e.g. in
photosynthesis or
respiration experiments). A bubble of gas is introduced into the short limb. This is then lowered
into reagent solution and
the bubble moved back and forth so that reagent diffuses through the end water seal. The
change in length of the bubble
indicates the amount of gas taken up by the reagent. Use potassium, hydroxide for C02
or alkaline pyrogallol for 02.
Dimensions long limb 250mm, short limb 100mm.
