Grandpa's Stuff

Yesterday I visit Grandpa at my Aunt's house, and he gave me a chemistry crash course, also some of his old stuff. Katanya kalau pakai yang Dow (the white one), harus ditaksir berapa kira-kira angka yang ada di antara skalanya. Dan ada 2% tingkat kesalahan dalam penaksiran itu. Kalau yang contoller, bilangannya cenderung bulat. But still, he said it's better to use nowadays calculator, because it doesn't have the 2% mistake rate.

[Jaqcuard paper bundle | The Dow Ruler, Calculator, and Table | Calculator-Controller from Amtraco]

[ My favorite, Grandpa said this can be used to calculate in knot]