Abstract: An apparatus (10) is constructed having a cylindrical enclosure (16) within which a disc-shaped wicking element (18) is positioned. A well or recess (22) is cut into an upper side (24) of this wicking element, and a glass cover plate or slip (28) having a protein drop disposed thereon is sealably positioned on the wicking element (18), with drop (12) being positioned over well or recess (22). A flow of control fluid is generated by a programmable gradient former (16), with this control fluid having a vapor pressure that is selectively variable. This flow of control fluid is coupled to the wicking element (18) where control fluid vapor diffusing from walls (26) of the recess (22) is exposed to the drop (12), forming a vapor pressure gradient between the drop (12) and the control fluid vapor.

Abstract: The invention is an optical cell for containment of chemicals under conditions of high temperature and high pressure and a method of making the optical cell. As shown in FIG. 1, the cell (10) is formed of a vitreous silica tube (14), two optical windows (16) comprising vitreous silica rod inserted into the ends of tube (14) and fused into position in the tube ends. Windows (16) are spaced apart to form a cavity (18) enclosed by the tube (14) and the windows (16). A hole (20) is drilled radially through the tube (14) and into the cavity (18). Another vitreous silica tube is fused to silica tube (14) around the hole (20) to form stem (22), which is perpendicular to the long axis of tube (14). The open end of stem (22) is used to load chemicals (12) into cavity (18). Then stem (22) may be sealed and, if desired, it may be shortened in order to reduce the volume of cavity (18), which extends into stem (22).