obviously this happened some time between the US Civil War and WW1 Nope. Howitzers and Mortars were used to fire from defilade prior to the US Civil War. WW1 was the first time that indirect fire gained dominance though, AFAICT.

Of course the Russians claimed to have used indirect fire in the late 18th C. As the 19th C progressed there were various arrangements for firing from behind crests, typically by putting a pole in the line between gun and its target beyond the crest but none really caught on. The key event was the German invention of the richtflache in about 1890, this was an azimuth scale with a rotating open sight that was mounted on the barrel just forward of the breech. It was quickly copied by other powers particularly the Russians as the ugloma. The optical sight emerged about 1900, the definitve design was German and patented by them. At this time it was usually translated in English as a goniometer or goiniometric sight, but the Brits adopted the term dial sight in about 1910. It's possible that there was some very limited use of indirect fire in the Boer War by both Boers and Brits but I still awaiting delivery of authoritaive sources to confirm this (recently reprinted after 50 years).

Thanks Neutraliser, knew you would be able to answer, next question then is when was the realisation made that max range actually was obtained at a QE of greater than 800 mils, and who were the first to start determining and applying MET to determin firing data?

If I understand your question, determining max range can be done mathmaticly & I seem to recall efforts to do this in Europe back in the 1600s. In any case the mathmatics of modern gunnery begain to pick up in the late 19th Century. From my reading of items published in the mid 20th Century the largest obstacle to mathmaticly accurate gunnery was (& may still be) getting consistent propelant charges. I'm hard pressed to recall any refrence to MET, other than guesstimated wind correction, before the Great War. Although I am open to info. I'll check my refrence list & see if I have any clues here. It is unfortunant my collection of the Journal of Royal Artillery does not go back that far. Sifting through the British literature I found some accounts of indirect fire in the Boer War. My take is it was a child of desperation as the Boers got some nasty blows in with their own guns.

I dont think I got across what I was asking for, what I wsa trying to ask was who were the first to "Put it all together" so to speak. Simple mechnics for projectiles in a vacume shows maximum range for any MV to occur at 800 mils QE, but who was it that realised that if you set QE higher the reduction in air density etc the higher you go actually gets you increased range. Is it FM6-40 or 50 goes into all this?

No you did not, but have now. I cant recall running across that particular item. A glance at the TFT reveals nothing, although there might be a consideration of it buried in the MET corrections tables. As far as someone seriously studying the question the officers of 'Paris Gun' of WWI are a candidate.

I'm not sure that there's an answer to the question about max elev. Upper register/high angle fire was, of coursed used in 'mortars', large calibre guns introduced in the age of gunpowder. Some heavy howitzers introduced in WW1 could shoot at elev up to 65deg. Before WW1 I've found nothing to suggest that any nation made any allowance for met, although there was recognition and some simple procedures to estimate and apply a correction for wind, surface wind of course. The 1910 edition of Bethall even provides a simple chart (of someone else's invention, can't remember the name) to calculate the head and cross wind components and also a means to calculate charge temp corrections. However, the real developments were during WW1. I can't throw any light on Russian practices, my knowledge of the French is the very little given in Gudmundsson's 'On Artillery. The Germans introduced the 'Pulkowski Method' in the winter of 1917/8. In essence this method corrected for variations in met and MV. However, Major Pulkowski was an offr on the small staff of Colonel Bruckmuller and it's not entirely clear if his method was adopted army wide or just locally. I suspect army wide because of the key underlying issue that everyone forgets - variation or correction data in range tables - and these data have to be developed. I don't know if earlier editions of GE RTS included the data and they just didn't bother with it, or if a staff decision was made in 1917, which caused the data to be developed and Pulkowski to devise a method of using it. It's possible that like the Brits they had some earlier and less effective methods. The Brit situation is a bit clearer, the RE who provided meteorological sections to GHQs offered wind data in 1915 but RA declined it, RE try to make something of this but the reality is the Brit RTs at that time did not have the RT data to use the met info. However, regular calibration was formally adopted in Jan 1916, and also in that month a succinct statement on met and related effects was issued by GHQ in France (GHQ Artillery Notes No 1), which also encouraged sorting ammo. They started issuing met msgs ('meteor telegrams') on 12 Apr 1916, twice daily providing wind data at 2000 and 4000 feet, air temp was added in August and in March 1917 they started issuing 6 msgs per day with data for times of flight between 7 and 50 seconds. In 1915 they seem to have undertaken range and accuracy firings in UK to enable them to produce RT data. I haven't yet got to the bottom of when the first RTs with correction data were issued, but the 1916 RTs give corrns for wind speed and direction, air temp, chg temp and bar pressure. The first were probably for RGA equipments since it was more important to them but I've yet to find them. These batteries had barometers and thermometers in early 1915, they could use this information by applying methods from the Textbook of Gunnery and calculating a ballistic coefficient for the day (RGA was more numerate than RHA and RFA!). However, RT data saved a lot of bother and allowed MET+VE type calculations (of course the Brits eventually got around the VE calculations by using gun rules, a much smarter solution). In 1918 wt corrns didn't start appearing in RTs, data for 60 sec ToF and bar pressure was added to met msgs, before this bar pressure was measured locally, Weighted data in met msgs (ie to give due weight to the time a shell spent in a layer) was also introduced in 1918. What all this shows is that the whole matter evolved quite quickly during 1915-18. I could go on, but one point to note is that the quality of met info probably left much to be desired. Radio sondes weren't invented until the late 1930s, this meant that wind was found by visually tracking balloons, and weather often limited max ht for this. Barometric pressure was used as a proxy for density, which was OK, air temp was extrapolated from surface air temp. These methods were basically those used by the Brits in WW2, although there seem to have been improvements to basic met data and atmospheric profiles and the War Office defined its own Standard Atmosphere in 1941. High angle fire was obviously a problem, basically the trajectory was too high for met data available.

That follows my haphazard reading on the subject. Just guessing, it is likely the officers of the longer range artillery battalions would have been exploring the possiblities in MET corrections the most aggresively. Even with accurate MET correction techniques the improvement is not critical at 3,000 - 5,000 meters range. At 10,000 or more the differnce is more noticable. particularly if one does not wish to find the correction through 30 minutes of adjusting single shots. It rather loses the element of suprise.

And in WW1 the really heavy guns such as 14 inch had a barrel life of about 750 rds so there was a certain keeness to make every one of them count. Of course in that war any Brit offr that spent 30 mins ranging fd guns would probably have been posted to infantry :-) The RGA, who ran the heavies had been mostly coast before the war and had always had a fairly scientific approach to gunnery.

I was refering to the long tedious method for determining 'will hit data' vs the 'should hit data' from the printed firing table. Bracketing the target with double rounds in four opposing directions each time one corrected range & deflection made for some very time consuming adjusting missions. Further the specialized slide rules, detailed & accurate correction tables, and accurate maps were unknown. Those guys were originally computing their firing data and corrections algebraicly with pencil & paper. The methods described in the Brit literature make the "charts & darts" I was originally trained in look highspeed.