Thus it is with these matters: but in the region to the West of lake Tritonis the Libyans cease to be nomads, and they do not practise the same customs, nor do to their children anything like that which the nomads are wont to do; for the nomad Libyans, whether all of them I cannot say for certain, but many of them, do as follows:—when their children are four years old, they burn with a greasy piece of sheep's wool the veins in the crowns of their heads, and some of them burn the veins of the temples, so that for all their lives to come the cold humour may not run down from their heads and do them hurt: and for this reason it is (they say) that they are so healthy; for the Libyans are in truth the most healthy of all races concerning which we have knowledge, whether for this reason or not I cannot say for certain, but the most healthy they certainly are: and if, when they burn the children, a convulsion comes on, they have found out a remedy for this; for they pour upon them the water of a he-goat and so save them.
— from The History of Herodotus — Volume 1 by Herodotus

Whether it ejects the rat or not I cannot say, but I should think that it is quite capable of doing so.
— from The Common Objects of the Country by J. G. (John George) Wood

Whether it was for this reason or not I cannot say, but the King immediately hurried back to Paris, instead of accompanying his wife to Bourbon-les-bains, as he had intended.
— from The Life and Letters of Ogier Ghiselin de Busbecq, Volumes 1 and 2 by Ogier Ghislain de Busbecq

“It is supposed to reach the Juba,” replied Guy, “but whether near the mouth of that river or not I cannot say.”
— from The River of Darkness; Or, Under Africa by William Murray Graydon

Whether it was the rum or not I cannot say, but in twenty minutes' time Bungle was able to bring up the rear guard with Kep.
— from The Sauciest Boy in the Service: A Story of Pluck and Perseverance by Gordon Stables