re: #874 SanFranciscoZionist

Temperature measurements were something of a consuming interest in the eighteenth century.

Having a crude thermometer and maintaining accurate records from diverse regions are two very different things.

Here is the excerpt from wiki which cites the appropriate papers:

A reconstruction is needed because a reliable surface temperature record exists only since about 1850.

Here

Here is a chart of the Instrumental Temperature Record as complied by HadCRUT3.

UNEP

This is well known by any real scientist, there are some regional records going back as early as 1659, the Central England Temperature data series, but nothing that qualifies as even quasi-global which starts around 1850.

Here is the Wiki overview which cites all its sources