Bill, i could not argue with your comments on WW1, at least regarding the technological advances that became evident in that war. I was mistaken in my comment that machine guns were used in the ACW, but the quotes I ioffered above indicate that there is an opinion held by some historians that 'modern' warfare was initiated during the ACW.
My initial comments focused on the terminology of this statement, "the first industrialised war in history" I proposed that that honor (or dishonor) belonged to the ACW,
You now want to change ths topic of discussion ever so slightly by saying, "However, World War One was the first time in which modern industrialised countries went to war with one another."
The ACW as the term implies was a civil war, though I guess one could construct an argument that the South's secession meant that it had become a separate nation. Of course, the North did not recognise the South's right to secede.
But the initial discussion was about the first industrialised war in history, not the first time that 'modern industrialised countries went to war with one another.'
This discussion could also focus on the precise meaning of a term like 'industrialised.'
There is evidence that there were industrial complexes in China built adjacent to coal mines, producing steel at least as early as the Song dynasty. (See John M. Hobson's, The Eastern Origin of Western Civilisation, Ch 3 and Ch 9,)
He also pffers a list of some remarkable weapons developed in Chinese history, which include Flame Throwers (circa 900 CE) Fire arrows (949) CE. Bombs, grenades and rockets (by 1231). Land and sea mines (by 1231) rocket launchers that could launch 329 rockets at a time. And Korea used a armored boat in a war with Japan in the 16th century.
My point is simple. what is progress? And what does industrialisation really mean? In this context, we are discussing an incremental change in the way things are done or made, and from that perspective, the ACW was a turning point as the historians cited in a previous post argued. Of course your welcome to hold a contrary viewpoint.