Well, the Citron bit is fairly obvious, in that it’s shaped like a lemon.
The Foug bit, not so much, and it’s quite difficult to find out much about the origin of this grenade, or at least to verify any of it, but Foug apparently refers to the commune of Foug in north eastern France (not, as far as I can ascertain, a company called Foug), where, despite being only a dozen miles behind the front lines, and subject to German air raids for much of the war, iron foundries churned out millions & millions of shell casings, and, it would seem, grenades too.
This was an extremely cheap and simple grenade to produce, allowing many different manufacturers to do so, and, despite its rudimentary operation, it apparently worked quite well, and was widely used from 1916 onwards.
The body of the grenade weighs around fourteen and a half ounces. Add three and a half ounces of explosive (cheddite) and the fuse, and you have a total weight of a little over a pound.
There are three holes drilled equidistantly around the neck of the grenade, but these are not threaded to accept a screw; wooden dowels (‘Cheville en bois’ in the diagram below) would hold the wooden fuse block (‘Bouchon de bois’) in place meaning that, like the ‘pear’ grenade we looked at last time, this grenade was supplied to the troops ‘live’ and ready to use. It was not until 1917 that someone realised that gluing the fuse into the body of the grenade instead was not only cheaper, but probably provided better waterproofing,…
…which presumably resulted in examples such as this, with no dowel holes, although in my experience, these are pretty rare (the photographs kindly supplied especially for this post by Paul N. – see comments at the end of the post).
This diagram shows the working parts, with a photo of the somewhat rudimentary fuse on the right. Striking the small percussion cap (‘Percuteur’ = striker) at the top on a hard surface would ignite the primer (‘Amorce’), in turn igniting the fuse, at the end of which was a crimped detonator which would explode after five seconds. The same would happen if you accidentally hit the percussion cap by falling or hitting something in the miry depths of a sodden communication trench,…
…so the ‘Capuchon de Sécurité’ (safety cap), was an important, if somewhat fragile, safety feature, which would undergo three changes as the war progressed, from the initial triangular cap on the left, to the round, and most common version, in the centre, to the much rarer, flat, late-war version on the right. At least I think that’s the right way round! Care still had to be taken, however, as the slits visible on all three caps allowed, if necessary, the grenade to be used without removing the cap, as illustrated in the small inset, top left of the diagram immediately below.
Entitled ‘Grenade C.F.’, as in Citron Foug, almost all these annotations are different from the first diagram. Note the regular percussion cap spring shown here, similar to the earlier black & white fuse photo, but different from that in the previous diagram, which features a leaf spring (‘Ressort à lame’) instead.
A French soldier shows off his array of armaments which includes a rifle fitted with a cup attachment and a couple of associated Viven-Bessière rifle grenades (perched on the box), beneath which, in the foreground,…
…there are half-a-dozen Citron grenades, the round caps of two clear to see, as are the bases (as in the photo below) of three others. Strangely, perhaps, despite its wide use, I have so far failed to find any other pictures of this grenade in action.
Citron grenades would also be adapted to be fired by slightly modified Guidetti launchers (these were 65mm, the original Guidetti – above – being 77mm), which you may remember I showed you near the end of a recent post,…
…by the simple addition of a wooden block (see inset top right). The Guidetti was actually an early attempt to supply the Poilus in the front lines with some sort of trench artillery, utilising obsolete weaponry – a cut-down Gras Mle 1874 rifle (see centre inset) with a reworked stock – attached to a ‘blunderbuss’ telescopic sleeve, surrounded by a large recoil spring.
The Citron Foug, despite its very basic design and operation, would prove a cheap and reliable grenade that would be used in vast quantities during the Great War and, if stories I have read about the North Vietnamese still employing captured Citrons against their former owners some forty years later are true, for some considerable time after.