The point noticeable here in reference to the accounts given by the various observers is the uniform assumption of right-handedness. Mr. Redding, Signor Craveri, and Mr. Cabot not only agree in describing the block of obsidian as held in the left hand, while the tools are employed in the right hand to fashion it into shape; but the whole language, especially in the description given by Signor Craveri, assumes right-handedness as not only the normal, but the invariable characteristic of the worker in stone. In reality, however, an ingenious investigator, Mr. F. H. Cushing of the Smithsonian Institution, while engaged in a series of tentative experiments to determine the process of working in flint and obsidian, had his attention accidentally called to the fact that the primitive implements of the Stone Age perpetuate for us a record of the use of one or the other hand in their manufacture. With the instinctive zeal of youthful enthusiasm Mr. Cushing, while still a boy on his father’s farm in Western New York, carried out a systematic series of flint workings with a view to ascertain for himself the process by which the ancient arrow-makers fashioned the flint implements that then excited his interest. After repeated failures in his attempts to chip the flint into the desired shape by striking off fragments with a stone hammer, he accidentally discovered that small flakes could be detached from the flint core with great certainty and precision by pressure with a pointed rod of bone or horn; and, as I have recently learned from him, the instrument employed by him in those experiments was the same as that which Dr. John Evans informs me he accidentally hit upon in his earliest successful efforts at flint-arrow making, viz. a tooth-brush handle. In thus employing a bone or horn flaker, the sharp edge of the flake cuts slightly into the bone; and when the latter is twisted suddenly upward, a small scale flies off at the point of pressure in a direction which can be foreseen and controlled. With this discovery the essential process of arrow-making had been mastered. Spear and arrow-heads could be flaked with the most delicate precision, with no such liability to fracture as leads to constant failure in any attempt to chip even the larger and ruder spear or axe-heads into shape. The hammer-stone only suffices for the earlier processes, including the detachment of the flake from the rough flint nodule, and trimming it roughly into the required form, preparatory to the delicate manipulation of edging, pointing, and notching the arrow-head. The thinning of the flint-blade is effected by detaching long thin scales or flakes from the surface by using the flaker like a chisel and striking it a succession of blows with a hammer-stone. The marks of this delicate surface-flaking are abundantly manifest on the highly-finished Danish knives, daggers, and large spear-heads, as well as upon most other flint implements of Europe’s Neolithic Age.