[Lowfer] Capacitor value in centimeters?

[John Bruce McCreath]

Hello Lowfers,

I have a book titled "Handbook of Technical Instructions for Wireless Telegraphists" dated 1918.
In it, the value of capacitors (condensers) is expressed in centimetres and/or jars, both of which
mean nothing to me.  I did a quick Google search for a conversion formula or table, but no luck.
Anyone here know how to convert capacitance expressed in centimetres into terminology that
we use today?

73, J.B., VE3EAR

LowFER Beacon "EAR"
188.830 kHz. QRSS30
EN93dr