 His view was based in part on the successful defence of Plevna in 1877 by Turkish forces using magazine-fed rifles and earthwork fortifications.Also, in 1882 following the heavy bombardment of the forts at Alexandria by the British Mediterranean Fleet, Clarke, as an engineer officer, had been given the task of assessing the damage to the forts.He found the bombardment had had very little effect on the earthwork defences with only 20 of the 300 guns having been dismounted.