Gas adsorption apparatus for determining the gaseous surface area of a material

In an apparatus for determining the surface area of a solid material which comprises fluid means for adjusting the volume of the apparatus, means for changing the pressure in the apparatus, a gas source for introducing a known volume of gas into said apparatus, means for recording the pressure of the apparatus before and after the introduction of said known volume of gas into said apparatus, and means for varying the temperature in a sample holder, the improvement comprising, a U-shaped manifold, said manifold having a base member connected to said apparatus and two substantially parallel conduit legs joined to said base conduit member, said base conduit member and said conduit legs defining a first plane, a plurality of conduits connecting a plurality of sample holders to the conduit legs, said conduits and said sample holders lying in planes which are transverse to said first plane wherein the conduits connected along one of said conduit legs are disposed substantially parallel to and off-centered from the conduits connected along the opposite leg.