Arranged in two double columns on the left-hand or bass jamb are 48 draw-stop knobs for the Couplers and Tremulants. The principal Couplers may also be operated by reversible pistons and the Tremulants (3) by reversible pedals. There are also 5 reversible pedal pistons for the Manual to Pedal Couplers. In addition to the usual Inter-manual Couplers there are on the Choir, Swell, Solo, and Echo organs Sub and Super and Unison (off) Couplers, each on its own Manual. A novelty is a coupler labeled Solo Tenor to Pedal. By its use the upper 20 notes of the pedal-board are available for a tenor solo by the right foot, at the same time the Pedal tones are cut off from these notes and the remainder of the pedal-board is available for use by the left foot as a bass. The stop control is effected in the first place by 9 Adjustable Combination Pedals to the Pedal Organ. Then there are 9 Adjustable Combination Pistons to the Choir, Great, Swell, Solo and Echo organs and 5 to the Tuba organ. It is possible to couple each set of these Manual Pistons to the Pedal organ Combination Pedals, either by draw-stops or by piston, thus moving pedal and manual stops synchronously. All these Combination Pedals and Pistons move the draw-stop knobs, showing a valuable index of their position to the organist. There are 5 Adjustable Pistons on the treble key frame (and 5 duplicates on the bass key frame) for special combinations, on Manuals, Pedal, and Couplers. There are 5 pedals to operate the various swell boxes of the lever locking type--a locking movement allowing the performer to leave pedal in any position. The swell pedal for the Pedal stops can be coupled to any of the others. The Tremulants have attachments allowing the performer to increase or decrease the rapidity of the _vibrato_ at will. The action throughout is electro-pneumatic and tubular-pneumatic (according to distance of pipes from keyboard), excepting the Manual to Pedal Couplers, which are mechanical to pull down the manual keys. There are seven separate blowing installations of electric motors. The instrument occupied two special chambers on each side of the chancel, and a portion of the south chancel triforium. There are four fronts, two facing the chancel and two (32 feet) facing the transepts. The console is placed on the north side above the choir stalls. The organ is the gift of Mrs. James Barrow and cost (without cases) about $90,000. The specification was drawn up by Mr. W. J. Ridley, nephew of Mrs. Barrow, with the full approval of her committee, Mr. Charles Collins, Mr. E. Townsend Driffield, the Cathedral organist, Mr. F. H. Burstall, F. R. C. O., and Henry Willis & Sons. It is claimed that this organ is now "the largest in the world." We give the dimensions of some notable instruments for the sake of comparison: