When did the term "scientist" overtake usage of the term "natural philosopher"?

The word scientist comes from the Latin scientia, but when did its usage become more prevalent than the term natural philosopher?

Solution 1:

From the data reported from the Corpus of Historical American, scientist started to be used more frequently than natural philosopher between 1860 and 1869.

The CoHA finds 538 phrases containing scientist dated 1960-1969, and 589 phrases dated 2000-2009.

Solution 2:

According to this blog post (and this), William Whewell proposed the term in 1835.

Opposition continued into the late 1800s and early 1900s, but according to this Google Labs ngram, the crossing point appears to be a little after 1870:

http://ngrams.googlelabs.com/chart?content=scientist%2Cnatural%20philosopher&corpus=0&smoothing=3&year_start=1800&year_end=1900

Solution 3:

I present a different picture:

Solution 4:

it probably happened in 1870 - just refined the Book Ngram Viewer

here's a more granular view - "natural philosopher" rallied but ultimately gave way to "scientist" before June of 1874