Much use is now made of video cameras to record underwater conditions which can then be viewed as a guide for maintenance staff.
Of 54 stations that test for heavy metals in five major rivers, 20 showed some improvement, but the majority, 31, showed no improvement, and 3 stations recorded worsening conditions.
He recorded meteorological conditions, gathered vocabularies of the local languages, taught the first pupils at the mission and undertook a vast official correspondence.
All other indicators are recording normal conditions.
No attempt was made to record the locations or conditions of damaged equipment in the turret.
Earlier this week, the Fed's Beige Book, which records economic conditions around the country, underscored that growth in most regions moderated in the period from June through mid-July.
For all the power of these images, though, what gives this show its punch is the pairing of Riis's pictures with those of photographers who are recording similar conditions today.
A weather station in Grayland, a community just south of Westport, has recorded conditions in the area going back to 1948.
And the initial findings are already upending old notions, among them that the Arctic Ocean lacked sufficient sediment and biological activity to record past conditions in its bed.
On Oct. 28, the society will send out volunteers to record conditions at public spaces to supplement the field surveys conducted in 1998 and 1999.