Maps

A Reddit post in r/Charleston led me to this cool online collection of pre-1945 USGS topographical maps at the University of Texas Libraries.

I love looking at old maps and seeing what areas used to look like and comparing them to modern maps to see how things have changed. The South Carolina collection has pretty good coverage of the Charleston area so I downloaded a few and went browsing around.

Here’s what the area just north of modern day Goose Creek looked like in 1919 (from the Summerville quadrangle map). Some of the roads in the 1919 map are still around, as is the rail line labeled Atlantic Coast.

1919 Goose Creek/Moncks Corner/Summerville
Part of the Summerville quadrangle 1919 USGS topographical map between modern day Goose Creek and Moncks Corner.

Here’s is a screenshot from Google Maps of the same area. Visible just below and right of center is the Google Data Center. You can also see the outlines of the swampy areas on the 1919 map are prominently visible.

2019 Goose Creek/Summerville
Google map area of the area between Goose Creek and Moncks Corner.

Maps can be so much fun.

Mah gimpy foot

I’ve been limping around on a messed up right foot for the past week since Field Day. Although the foot has gotten a little better since last week, it’s still somewhat painful to walk on and there’s still a bit of swelling going on (enough that my foot doesn’t fit into my shoe very well anymore).

Made an appointment to see the doctor, and got some x-rays on my foot. Good news is that according to the radiology report, there are no fractures and no bones out of place. Just some soft tissue swelling.

Got a referral to orthopedics so in the meantime, rest, hot/cold compresses for the swelling, and ibuprofen for the pain as needed.

300V in a battery

One of the exposure meters in my collection (a Radcal/MDH 1515) uses this Eveready #493 300V battery as bias voltage source for the ionization chamber used to measure x-ray exposure. The rest of the meter is powered by 4x2V rechargable lead acid batteries in a D cell form factor.

Looks like this battery was installed in December 2002. Last calibration date for the meter was 2003, so it was probably replaced when it was sent in for the previous calibration.

Installed December, 2002
Installed December, 2002

After 16 years of sitting on the shelf, the battery is pretty flat.

Dead battery
Battery’s pretty dead

Let’s take the cardboard off and have a look at what’s inside.

There are 10 plastic wrapped packs, each 1.3 cm x 2.2 cm x 6.6 cm long, all connected in series. Each pack appears to have 20 individual cells coated in a waxy type material and wrapped in plastic to hold them all together. With 200 cells, that gives 1.5 V for each cell.

Looks like there’s been a bit of leakage while the battery sat on the shelf for the past 16 years.

A little bit of leakage
A little bit of leakage

A close up of one of the packs.

Inside the Eveready 300V #493. Close up of the cells
Inside the Eveready 300V #493. Close up of the cells

Neat stuff.