In the top sketch we see the most common cross-section for the forward part of a ballista’s stock. The dovetailed slot is where a separate slider would track going in and out of the stock.

The bottom sketch shows the cross section of a stock that utilizes a non-moving rail system for the catch assembly to ride on. The grooves at points 1 and 2 form the underside of the rails. This is a system that has worked extremely well on Firefly. It is many times superior to the old, full length slider system that I had on my Gallwey. I daresay, rail type systems are many times the functional superior of conventional, long, wooden sliders. I’ve tried ’em both extensively, and speak about this with over 1000 rounds of ballista fire under my belt. Urp!

Just sayin…..

So, what to make of the famous original carving, seen below?


Photo supplied, and the carpentry elegantly photoshopped, by Mr. Randi Richert.

The simplest and most literal interpretation of the incised line (see red arrow) seen in the fore-end of this ancient depiction of a ballista, is that it most nearly resembles the two grooves seen in the rail type design mentioned above, (i.e. bottom sketch). The long wooden slider style (top sketch) shows only clean, ungrooved surfaces on the side of the stock. Also, if you magnify the forward part of the stock in the above photo, it is clear that the incised line and the rail that it represents, goes all the way to the end. This is important because that would allow a moving catch assembly to slip on and off for maintenace purposes.

Occam’s razor suggests the simplest explanation to match all the facts, ……..etc, etc.

Maybe the pesky old Roman that carved the INCISED LINE, was going for a racing stripe look or something….. Not much Occam in that line of thinking, though.

Therefore, the simplest interpretation is that the incised line on the carving represents one of two grooves for a rail system that utilizes a moving catch assembly to hold the bowstring. Not encumbered by a long length of wooden slider, it can run up and down the rails while the bolt groove remains static. In short, just like Firefly.

2 Responses to “The incised line.”


  1. Randi Richert says:

    You’re absolutely right. That’s why every image on Trajan’s has what the “experts” refer to as the “slider” sticking far forward of the frame, no matter if is drawn and has a bolt loaded or not. IMHO the big difference between Heron’s original Cheiroballistra and the Carroballista is that without a slider, the stand-mounted version does not need any of the case to project beyond the ladder. Because the Cheiroballistra is essentially an updated Gastraphetes it needs a slider and thus a dovetailed forehand to support it when extended. The winched, stand-mounted version doesn’t, so all you see is the grooved base (canalis fundus or quadratus stylus if you prefer) projecting beyond the frame. This is one of the major benefits of the iron-framer. With the case half as long between the column and the winch, it could be used from the back of a mulecart or along a fortress wall. That is why Orsova sized outswingers are virtually useless. With a one-meter tall column and a nearly three-meter length, they can’t be fired at a steep enough angle to take advantage of their full range. I’ve seen photos from an event at Lafe where they had to remove the winch handles from Taurus Magnus to get it to fire over the walls of the camp.


  2. nick says:

    Elementary, my Dear Randi, and thank you for these insights.

    Also: logic dictates that Firefly can be shortened by at least 15″. That makes my sensibility molecules start to vibrate. Yuk! But, follow the logic we must, because if we don’t we get stuck in the trap of making a “pretty” ballista that conforms to the expectations of the crowd. On that, I would much sooner have a machine that exceeded expectations on the range than pleased the judges at the poodle show. Performance is everything (all the usual caveats applied) because it is so sweetly, sweetly Roman.

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