“On the door (or table) there is a lot of bowls, jugs, plates, jam pigs, etc., containing water, salt, soda, sulphuric acid, blue vitriol, plumbago ore; also broken glass, iron, and copper wire, copper and zinc plate, bees’ wax, sealing wax, clay, rosin, charcoal, a lens, a Smee’s galvanic apparatus, and a countless variety of little beetles, spiders, and wood lice, which fall into the different liquids and poison themselves. I intend to get up some more galvanism in jam pigs; but I must first copper the interiors of the pigs, so I am experimenting on the best methods of electrotyping. So I am making copper seals with the device of a beetle. First, I thought a beetle was a good conductor, so I embedded one in wax (not at all cruel, because I slew him in boiling water, in which he never kicked), leaving his back out; but he would not do. Then I took a cast of him in sealing wax, and pressed wax into the hollow, and blackleaded it with a brush; but neither would that do. So at last I took my fingers and rubbed it, which I find the best way to use the blacklead. Then it coppered famously. I melt out the wax with the lens, that being the cleanest way of getting a strong heat, so I do most things with it that need heat. To-day I astonished the natives as follows. I took a crystal of blue vitriol and put the lens to it, and so drove off the water, leaving a white powder. Then I did the same to some washing soda, and mixed the two white powders together, and made a small native spit on them, which turned them green by a mutual exchange, thus:--1. Sulphate of copper and carbonate of soda. 2. Sulphate of soda and carbonate of copper (blue or green).” Of his reading he says:--“I am reading Herodotus’ ‘Euterpe,’ having taken the turn--that is to say that sometimes I can do props., read Diff. and Int. Calc., Poisson, Hamilton’s dissertation, etc.” In September he was busy with polarised light. “We were at Castle Douglas yesterday, and got crystals of saltpetre, which I have been cutting up into plates to-day in hopes to see rings.” In July, 1849, he writes[12]:-- “I have set up the machine for showing the rings in crystals, which I planned during your visit last year. It answers very well. I also made some experiments on compressed jellies in illustration of my props. on that subject. The principal one was this:--The jelly is poured while hot into the annular space contained between a paper cylinder and a cork; then, when cold, the cork is twisted round and the jelly exposed to polarised light, when a transverse cross, X, not +, appears, with rings as the inverse square of the radius, all which is fully verified. Hip! etc. _Q.E.D._” And again on March 22nd, 1850:--