MIRACLES AND SPECIAL PROVIDENCES. 363 
from which distances must be measured to bodies attracted 
by the earth. 
From experiments executed before his time, Newton 
knew the amount of the earth's attraction at the earth's 
surface, or at a distance of 4,000 miles from its center. 
His object now was to measure the attraction at a greater 
distance, and thus to determine the law of its diminution. 
But how was he to find a body at a sufficient distance? 
He had no balloon? and even if he had. he knew that any 
height to which he could attain would be too small to 
enable him to solve his problem. What did he do? He 
fixed his thoughts upon the moon a body 240,000 miles, 
or sixty times the earth's radius, from the earth's center. 
He virtually weighed the moon, and found that weight to 
be one thirty-six hundredth of what it would be at the earth's 
surface. This is exactly what his theory required. I will 
not d well here upon the pause of Newton after his first calcula 
tions, or speak of his self-denial in withholding them because 
they did not quite agree with the observations then at his 
command. Newton's action in this matter is the normal 
action of the scientific mind. If it were otherwise if 
scientific men were not accustomed to demand verification 
if they were satisfied with the imperfect while the perfect 
is attainable, their science, instead of being, as it is, a 
fortress of adamant, would be a house of clay, ill-fitted to 
bear the buffetiugs of the theologic storms to which it is 
periodically exposed. 
Thus we see that Newton, like Torricelli, first pondered 
his facts, illuminated them with persistent thought, and 
finally divined the character of the force of gravitation. 
But, having thus traveled inward to the principle, he 
reversed his steps, carried the principle outward, and 
justified it by demonstrating its fitness to external nature. 
And here, in passing, I would notice a point which is 
well worthy of attention. Kepler had deduced his laws 
from observation. As far back as those observations 
extended, the planetary motions had obeyed these laws; 
and neither Kepler nor Newton entertained a doubt as to 
their continuing to obey them. Year after year, as the 
ages rolled, they believed that those laws would continue 
to illustrate themselves in the heavens. But 'this was not 
sufficient. The scientific mind can find no repose in the 
mere registration of sequence in nature. The further 
