The engraving is from The Graphic page 460 10th May 1879. Here's the text as exactly as written;
WITH THE NATAL NATIVE CONTINGENT - OFFICERS' DRILL
"THIS engraving represents," says Dr. Doyle Glanville, to whom we are indebted for these sketches, "a very amusing scene I witnessed the other day at the camp at Krantz Kop, Natal frontier, where the homes of the Natal Native Contingent are stationed.
"In order to accustom the horses to the noise of the rattling of the shields and assegais, which is very startling to ears unfamiliar to the sound, and which is a mode of approaching the enemy usual with the Zulus, it was thought advisable for the officers to charge some of our native soldiers, who, on the other hand, were to rush on like the enemy. Officers and men duly fell into their respective lines, 'charge' came the word, away went the opposite parties at one another, the natives rattled their shields, and nearly all the horses were so astonished, that away went some, other stopped, or kicked and plunged or reared, others turned tail full speed, while many a gallant warrior sprawled ignobly on the ground. Next time the riders were cautious!"
Source: A well Known Zulu War Historian.