If he [Thomas Edison] had a needle to find in a haystack, he...

If he [Thomas Edison] had a needle to find in a haystack, he would not stop to reason where it was most likely to be, but would proceed at once with the feverish diligence of a bee, to examine straw after straw until he found the object of his search. ... [J]ust a little theory and calculation would have saved him ninety percent of his labor.