...To speculate was to wound himself in vain... 
Rafael Sabatini 「Captain Blood」
...If we are to speculate on the mannerin which the Sorex vagrans rassenkreis originated we must inquireinto the nature and extent of these climatic changes...
James S. Findley 「Speciation of the Wandering Shrew」
...It is as yet unsafe to speculate concerning the origin of thisimplement...
Otis T. Mason 「Throwing-sticks in the National Museum」
... Scholars have sought to fix the chronology of the poet's works, and have been tempted to speculate upon the evolution of his literary and moral ideas...
Chretien DeTroyes 「Four Arthurian Romances」
...It was useless, to speculate, however;time would show it to him...
Arthur J. Burks 「The Mind Master」
...It is curious to speculate on what might have been thehistory of astronomy had Venus only been as large as Jupiter...
Robert Stawell Ball 「The Story of the Heavens」
...It appears, therefore,useless to speculate on the probable actions of men in their nowterrestrial prison...
Cecil G. Dolmage 「Astronomy of To-day」
...I speculate if I shall ever be one of those grotesque and melancholy beings, with bleared eyes and running noses, swollen bellies and shrunken legs! Ugh!—it is too likely...
Marcus Clarke 「For the Term of His Natural Life」
...He then went on to speculate as to the cause of the planets' motion...
Oliver Lodge 「Pioneers of Science」
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