[Jounral entry for June 28, 2017; Environmental measurements on the Hudson River] My friend Bob Rasmussen volunteered to take LDEO grad student Elise Myers, LDEO Summer Intern Arianna Medina and me (Bill Menke) on a morning cruise on the Hudson River, in order to collect particle size data. We met Bob at Cornetta’s Restaurant and Marina at 10 AM and boarded Viking, a 28-foot motorboat. We deployed the particle size meter, suspended on the Nautilus float that I built several weeks ago and that we were trying out for the first time. I was relieved to find that I had designed it with sufficient flotation, for I was not sure just how much the meter weighed. It floated, and tracked very well, too. Bob steered a broad loop of this part of the river, reaching the Westchester side at Matthiessen Park in Irvington New York. We watched Viking’s bathymetric display with interest, seeing the river bottom deepen from five feet at the marina to about fifty feet in the channel. The display occasionally showed water column returns that we supposed were fish. Fish were indeed present, for we saw one jump six feet high in the air – an amazing feat for a foot-long animal. We returned to Cornetta’s at about noon, and after stowing the gear, had a leisurely lunch at the dining tent behind the main restaurant building. 2:00.