Individual solar cells are somewhat difficult to solder to. Self-adhesive metal stained-glass tape makes for the easiest soldering job--the tape holds itself in place while you solder. Use electronics solder that contains 2% silver. One side of the cell is (+), the other (-).
rain check (plural rain checks) (idiomatic) Any voucher or note from a merchant to a customer to provide an item the merchant has run out of at a later date for the item's current price, or (in a more literal sense) to provide a service at a later date.
Latter rain in the Bible literally refers to spring rains. Former rain refers to autumn rains. The terms latter and former rains are used in the King James Version of the Bible. Some newer translations, such as the New International Version, use the terms autumn (or fall) and spring rains.