In Modern Warfare a great proportion of the work of artillery is carried out, of necessity, in the hours of darkness, owing to the frequency of movement by night to avoid aerial observation, and to the consequent use of indirect artillery fire to inflict losses during such movements. The artillery personnel therefore requires to be relieved with greater frequency than in the days before the use of aircraft. The growth of artillery during the war was symbolical of the continual changes in the methods of warfare, its numbers and power increasing out of all proportion to the experience of previous wars. "The 486 pieces of light and medium artillery with which we took the field in August, 1914, were represented at the date of the Armistice by 6,437 guns and howitzers of all natures, including pieces of the heaviest calibre" (Sir D. Haig's Dispatches). "From the commencement of our offensive in August, 1918, to the conclusion of the Armistice some 700,000 tons of artillery ammunition were expended by the British Armies on the Western Front. For the fortnight from August 21 to September 3, our daily average expenditure exceeded {170} 11,000 tons, while for the three days of the crucial battle on September 27, 28, and 29 (_Second Battle of Cambrai_) nearly 65,000 tons of ammunition were fired by our artillery" (Sir D. Haig's Dispatches). In the Table of Artillery Ranges on p. 173, the effective ranges of light artillery firing H.E. shell are based on the use of No. 106 fuse. "The invention of a new fuse known as '106,' which was first used at the _Battle of Arras_ (April 9-June 7, 1917), enabled wire entanglements to be easily and quickly destroyed, and so modified our methods of attacking organised positions. By bursting the shell the instant it touched the ground, and before it had become buried, the destructive effect of the explosion was greatly increased. It became possible to cut wire with a far less expenditure of time and ammunition, and the factor of surprise was given a larger part in operations" (Sir D. Haig's Dispatches). Artillery is classed under the designations Light, Medium, Heavy, and Super-Heavy.