I just received my first issue of The E-Sylum. Thanks for the welcome as a new member. It was the recent article in Coin World by Joel Orosz that prompted me to sign on. I just spent 30 minutes cruising the articles and candid responses and found that Joel was not exaggerating in his glowing article.

I found the names of many numismatic friends, acquaintances and luminaries that I truly admire. My first inclination is to take a week off of work and spend the time exploring your wonderful creation and the remarkable ongoing input from so many people.

I'm sure that you will be hearing more from me once I read, absorb and learn to navigate E-Sylum. Keep up the great work!

David Buik on the English penny: "After losing several hundred per cent of its value in the past two to three decades,..."

How, pray, does an item lose more than all of its value? It enters negative value, so is actively dangerous to have around?

I was looking to purchase a copy of the World Notgeld 1914-1947, 2nd Edition Cd-Rom that you wrote about in the last E-Sylum. The link pointing to www.shopnumismaster.com does not work. I even went the their website and could not find it. I could not find where to purchase this item even after hours of Internet searching. Any idea on where to get hold of a copy of the CD-Rom?

I stumbled upon the website coinvideo.com in which I found a video DVD of a talk I did at the American Numismatic Association convention in 2004 for sale at $25, I did not recall that such a video was even made. If the copyrights are still with ANA, they should all be put free on YouTube

This illustration is also in "A Handbook to the Coinage of Scotland" by J. D. Robertson, printed by Argonaut, Inc., Chicago in 1968. It is in the introductory chapter on page xiv.

"A major challenge with using banknotes is their rough fibrous surface, which necessitates adding a planarization layer to render the surface amenable to electrode and active layer deposition," says Alshareef. "We overcame this problem by applying a planarizing layer of polydimethylsiloxane (PDMS). In addition to acting as the planarizing layer PDMS provides other important roles such as providing adhesion and strain isolation for the devices above. A key feature of PDMS layer is that it penetrates deep into the fibers of substrates such as banknotes, thus providing strong adhesion without chemical bonding."

In regard to the article on RFID-tagged money, the above paragraph raises questions. I checked the reference provided, but could get no further than the abstract without a membership in the source site. I realize that the following might be too esoteric to be of interest, but here it is just in case.

PDMS, polydimethylsiloxane, is an inert polymer that might fill in spaces between, without binding to, fibers. But I doubt there would be any lasting retention as needed in something like circulating bank notes. At high molecular weights (number of repeating units), PDMS (with added silica, which is basically sand) is just silicone grease, and at lower MW without filler, it's silicone oil. Both are lubricants that work by not actually binding to anything. There are many modified dimethylsiloxane polymers, however, with other atoms deliberately built in that might afford the article's stated adhesion properties. So I wonder just what the polymeric bank note substrate is and whether the authors really mean PDMS, and of what molecular weight.

Further, the topmost of the 4 images in the graphic is a group of cyclic chemical structures. It does not represent PDMS (if it's supposed to) and looks more like a group of aromatic hydrocarbons. PDMS is linear, not cyclic, except for components of extremely low molecular weight. PDMS has two methyl groups, not one, attached to each silicon atom, which in turn is attached to one oxygen atom in repeating units, e.g. -Si(Me2)O- linked together in a repeating chain.

However, this article on RFIDs is another great example of just how far-ranging the field of numismatics really is. This core subject of ours involves chemistry, physics, and metallurgy as well as history, politics, and art. I think that a great course could be taught in colleges on just this idea, and I wonder whether that might actually be going on somewhere. One could call it, "Money, it's everything."