Top Cylinder Inverse Action Marvel Mystery Oil Tank in Eng Compartment

Check out the large oil container on the lower right on this thumbnail page 
of pictures. 

What is the function of this added capacity for oil?  Does it simply allow 
the motor to run on a larger oil capacity?  Or does it have something to do 
with 
getting oil to the top of the pistons on start up - or?

http://www.spritespot.com/gallery/59-Austin-Healey-Sprite?page=10



Thanks!

Kirk 
59 1275 Bugeye