Harris Visible, page two; a Harris, Rex and Demountable Gallery
Jim dax has sent much ad copy, and the clip at left is from a 1916 ad for the Rex Visible, and the Rex Typewriter Company. 

The ad has much fascinating information.  The general manager of the company, a Mr. Ballard, states that he's been in the typewriter business for twenty years and has never offered a machine or deal like this.  He notes that the Rex is not a toy, and is as expensive to manufacture as the common $100 standards.  Lack of any dealer network allowed a much lower price.  Solicitations like these were used to sell the machines.  The machines also had an unparalleled ten year guarantee against defects.
In terms of variants within the production of the three bank machines, one of the most obvious is that of ribbon selector.  My machine has no ribbon selector at all.  Cuyler's machine, a Rex, has the front mounted three position ribbon selector.  The Rex in the shot above has ribbon selector knobs on its sides.  It should be noted that some machines with no ribbon selector do, in fact, have a break in the metal bead, or trim line, where the hole for the operating shaft for the selector (of the front mounted kind) would be.  So, then, we have four variants.
Esteemed collector Richard Polt sends us this shot of his Harris Visible.  It is serial number 14396, and is a No. 4, of course.  It gives the "Harris Typewriter Manufacturing Co." label, and has no ribbon selector.

On the right, Harris Visible ad for the machine when sold through Sears by mail order.
Chuck Dilts and Rich Cincotta send this shot, at right, of their Harris Visible No 4.  This is serial number 15454.  It has no ribbon selector, and no break in the trim line for a front mounted, lever type.  This is, then, the first production phase.
Chuck & Rich also send this shot of their Rex Visible No 4, which is serial number 46314.  It appears to carry the "Sold and Guaranteed by American Can Company Chicago USA" label, and has the front mounted ribbon selector.
At right, we see a machine from the collection of Tilman Elster.  This is his Harris Visible No 4, serial number 15430.  It has no ribbon selector.  It does include the reference to Harris Typewriter Manufacturing Co. in the decal on its frame.
Tilman also sends this shot, of his Rex Visible No 4, which unfortunately is missing its paper table.  However, of great interest are the side mounted, knob type ribbon selectors and the label on the frame stating that it was made by the Rex Typewriter Company.  This machine is serial number 8407, and was the first shot sent to us that matches the machine seen in the Rex advertisement seen at the top of this page.
Tilman's final shot is the most intriguing.  This machine is actually a Rex Visible No 10.  It is serial number 50852.  It appears to have one more character key, thus three more figures possible, than the other three bank machines.  The frame, again, gives the name of Rex Typewriter Company.  Two examples of this model are known to exist.
Above and right, Chuck & Rich.  This is the 'end of the line,' so to speak, which is the Demountable.  The reason for this name should be obvious -- and the operation doesn't take much time at all.  This company, namely the Demountable Typewriter Company and the associated Demountable Typewriter Company Incorporated, bought the remains of the Rex Typewriter Company after its failure.  Apparently, this machine had already been designed.  Final serial numbers available for these give a 1934 date, and while other sources give 1936 for an end to the company itself, the state records in Wisconsin give a final sale/dissolution of assets date of 1939.
Demountable No2, serial 139361
John Pulley sends these shots of his Rex Visible No 4, serial number 9376.  Has label "Manuf'd by Rex Typewriter Company, Fond du Lac, Wis."  He notes that it's in as-found condition, which appears from here to not be all that bad.  Note that this is the second lowest serial number yet found for any machine of this line -- Tilman Elster's Rex Visible No 4 is the only one lower, at 8407.
You might ask what the highest known serial number for any machine in this line is, in view of the above.  Here is that very machine!  From the collection of Herman Price.  This is one of two known Demountable No 5 machines, and it has serial number B150698.  Only the two Demountable No 5 machines (and one unnumbered machine) carry letter coding with their serial numbers, for yet unknown reasons.  No matter the exact date, be it 1934 or 1936, this is the end of the line for the whole Harris-Rex-Demountable family.
The biggest mystery at the moment concerns the seven known Harris Visible No 4 machines which carry six-digit serial numbers, running between 103337 and 111533.  My machine, seen here, is one of them (being 106723.)   These machines may include an extra first digit of "1" on the front of the serial number to indicate distribution or use by Sears-Roebuck.  This would then make my machine, sequentially, the 6723rd built.  If this is actually the case, then the "1" prefix machines run from the start of production up through s/n "11533" mentioned above.  The numbers then revert to conventional five-digit serials.  One figure that can be guessed from the known serials is that Harris built no more than 25,000 units, probably less.
Chris Amato sends us these pictures of a newly-discovered and intriguing labeling variant.  This machine is outwardly a fully conventional Harris Visible No. 4.  It has the break in the decorative bead on the front panel where a ribbon selector switch would be fitted -- omitted on this machine.  Inspection reveals that it not only has a six-digit serial number (105462) but is labeled, on the front frame, in a manner not yet seen.

The blown-up shot of the front frame below displays the fact that, while the machine is overall labeled as a Harris Visible No. 4, it was 'Manuf'd by Rex Typewriter Mfg. Co., Fond du Lac, Wis."  It is immediately apparent that the decal has been modified; note the gap left for the name "REX," which is still wide enough to include the original name of "HARRIS."  None of the various corporate Rex permutations included the word "manufacturing" in its papers of incorporation.  This may indicate that the last batches of Harris machines were early units actually refurbished, or late unbuilt units completed, by Rex.  It only further blurs the mystery of those machines which carry six-digit serial numbers.