Hello James: I'll be sending you your copy today of thomas' chapter on the precipitation of colloids by electrolytes. No charge. Please share it with others. I will use the ZIP code 87562.
Freundlich's assay method will require some gravimetric apparatus as a primary standard. I will probably be buying a small twin-beam balance for my own use, even though I do have access to an analytical balance. I want to gain experience with less expensive apparatus. I have had good results with patronizing American Science and Surplus in Illinois. They have catered to small-purchasers, amateur experimenters, home-schoolers, etc., for many decades. They are selling miniature twin-beam balances for $35 and $13. Another possible good deal is from Deutche Optik in San Diego CA. They are advertising an Army Medical Balance from eastern europe for $199. But that is a bit out of my price range. I followed David's recommendation and looked into water softening KCl at Lowe's. Forty pounds costs less than $9 - and this would probably supply the whole world for purposes of Freundlich's assay! I think Lowe's sells broken bags for half off. But only one or two chunks should do for a long, long time. After I get some experience with NaCl and KCl, I may try potassium iodide. KI is readily available in pre-measured tablets nowadays. It may make a good comparison with KCl. Best wishes, Matthew
