I'm looking for a Merit #4 set, the later model with the updated box (not the one with the kid in the tie) and ideally a white rather than blue
internal plastic tray. Must be good condition and be willing to ship to the USA. Will pay handsomely for a great example.
Also interested in Thomas Salter sets, especially the earlier style in the large flat blue boxes. a #7 would be great. Also interested in parts from
these earlier sets.
Email me directly at paulr1234@yahoo.comgdflp - 20-7-2014 at 11:14
Check out this eBay auction for the Merit chemistry set.
[Edited on 20-7-2014 by gdflp]Artemus Gordon - 20-7-2014 at 12:12
I see the set on EBay contains logwood. I seem to recall that nearly all chemistry sets contained logwood. Does anybody know why? Wikipedia says it is
a source of dye, but doesn't elaborate much. Was it used as some kind of an indicator? Artemus Gordon - 20-7-2014 at 13:18
I see the set on EBay contains logwood. I seem to recall that nearly all chemistry sets contained logwood. Does anybody know why? Wikipedia says it is
a source of dye, but doesn't elaborate much. Was it used as some kind of an indicator?
Well, I did some poking around both SM and Google. It appears that many other people were baffled by those splinters of wood in their chemistry sets,
but I did find this:
Edward Bancroft (1744–1821), scientist, writer, spy and double agent was elected a Fellow of the Royal Society in
1773 as “a gentleman versed in natural history and Chymistry, and author of the natural history of Guiana”. He
sang the praises of logwood:
Sulphate of copper added to the decoction of logwood, gives it a purplish blue colour; sulphate of zinc
added to a similar decoction, produces a dark purple; nitro-muriate of gold, an orange; muriate of
quicksilver, an orange red; muriate of antimony, a beautiful crimson; acetate of lead, a garter blue; arseniate
of potash, a deep yellow; muriate of barytes, a reddish purple; nitrate of barytes, a brownish purple; stronta
earth, a violet; sulphate of magnesia, a purple; muriate of magnesia, a yellow; sulphate of lime, a purple; and muriate of lime, a violet purple.
These effects show that the tingent matter of logwood, is capable of
producing, with different mordants or bases, almost all the possible varieties of colour [4].
So I guess it could be used as a test for various chemicals. It also seems to be pH sensitive (although I would have thought that phenolphthalein
would have been a better choice for a kit, since it was in common use as a laxative).
(From <a href="http://www.chem.qmul.ac.uk/rschg/Newsletter/NL2014winter.pdf">Royal Society of Chemistry Historical Group Summary of
Papers</a>nezza - 21-7-2014 at 23:20
I think logwood was an impure form or another name for haematoxylin.unionised - 22-7-2014 at 13:11
