539 
ON FAILURES AT PRACTICE WITH THE TIME 
AND PERCUSSION FUZE MARK IV. 
— BY — 
MAJOR W. A. URQUHART, late R.A. 
THE results obtained by batteries at practice when using the same 
mark of fuze, the Time and Percussion Mark IV., vary so widely, 
there being in some batteries no failures at all, whereas others have as 
many as 10 per cent, that there can be no doubt that a very large 
proportion of the failures are due to preventable causes and not to 
defects in the fuze or shell. 
It may, therefore, be of some use to officers who use the fuze, if I 
mention all the causes of failure that have come to my knowledge and 
make a few remarks on them. 
A. — Blinds or reported blinds may be due to 
1. Safety pins not pulled out or broken off in pulling out. 
2. Defective fuze. 
3. Bad clamping. 
4. Weak shell. 
5. Spindle of fuze or head of shell breaking off on impact. 
6. Distortion of fuze or head of shell on impact. 
7. Features of ground concealing the burst. 
8. Faulty observation. 
9. Shell smothered in soft ground. 
10. Range too short for percussion arrangement to act with 
certainty. 
B. — Shot bursts or bursts in bore may be due to 
11. Bad setting. 
12. Bad clamping. 
13. Both safety pins being withdrawn (when firing ranging 
shots). 
U. yol. xxv. 
