ST Applications

LEWIS123

One of the first pure-science applications for the ST, Lewisl23 (Version 3.0) is billed as a spreadsheet for chemistry. This is misleading because the program bears no resemblance to Lotus 1-2-3 of spreadsheet fame. Instead it is a sketchpad for drawing two-dimensional molecular structures built according to the Lewis theory of covalent bonding (familiar to any trained chemist).

Drawing molecular structures is straightforward. Up to 460 chemical elements per structure can be selected from menus, dragged to desired locations and have bonds (lines) drawn between them by clicking. Only covalent bonds are supported. Elements that preferentially bond by other means (transition metals and rare earths) are not included in the selection menus.

Warnings are given for bonds that would violate the Lewis theory. An option is available to ionize elements in order to give (or force) bonds in agreement with theory. Once a bond is formed between two elements, it is maintained no matter how the elements are subsequently moved.

The position of bonds between two elements is determined solely by program logic and can lead to structure diagrams that are chemically valid but aesthetically poor. The manual suggests trial and error to remove and recreate bonds to improve the plot quality. A snap grid template can be used to aid in positioning elements.

You can cut and paste variable-sized blocks of a structure, either an entire molecule or a piece of it. These blocks can be used to speed drawing structures with repeating units or stored on disk as a library of building blocks. Block rotation is not supported and is sorely missed.

Lewisl23 is not copy-protected. It requires a monochrome monitor. A printer is optional to provide hardcopy of the structures. An Epson printer driver is supplied (DEGAS.P13 format). Users with other models must provide their own DEGAS printer drivers.

The accompanying manual does a good job of covering program function, but desperately needs proofreading. A slide-show program is included.

Besides drawing, Lewisl23 can analyze formal charge, determine the theoretical bond requirement for a given set of elements, and provide reference data on individual elements. While of some theoretical interest, these options are not well implemented. The theoretical bond calculation applies only to all unbonded elements on the screen and gives meaningless results when used to verify a structure. The element count screen shows all available elements, whether used or not. A simple molecular formula and molecular weight would be far more useful and less cluttered When everything works, Lewisl23 can generate good-quality molecular structure diagrams. Users who want to just draw structures should test the program first. A demo version is widely available on bulletin boards. Given the amount of work needed to draw a structure and the monochrome restriction, you may well opt to just use a more powerful drawing program like DEGAS in the first place.

$29.95, monochrome only. Stone Age Software, P.O. Box 1216, Amherst, NH 03031. (603) 881-7689.

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FONTS & BORDERS

Fonts & Borders is the latest addition to the growing PrintMaster Plus design library. With 3 collections of clip-art graphics now available (Art Gallery I, II, III), this newcomer addresses another printing need- additional text fonts and border styles. Fifteen new fonts and 20 new border designs are provided, with 3 of the fonts in multiple sizes.

The fonts are all attractive and cover a wide range of styles from elegant to backwoods. The border designs are equally impressive. Some seem destined for fame, such as the dinosaur and Halloween borders. Whatever the occasion, you are guaranteed to find appropriate designs.

A patch program also is included to automatically upgrade the original PrintMaster program to the current PrintMaster Plus. Since I bought my copy just before the new version came out, I really appreciate this bonus. The upgrade only takes a couple of minutes and then you are ready to go. You must have the upgraded program in order to make use of these additional fonts and borders. The program also comes with a catalog of related products including colored paper, heat transfer ribbons (to create customized T-shirts) and a manual of applied graphic design.

I am very pleased with the quality and number of additional fonts and borders provided in this package.

Unison World has an excellent program in PrintMaster Plus and continues to support and extend its applications with these additional library collections.

$29.95, color or monochrome. Unison World, P.O. Box 3056, Berkeley, CA 94703. (415) 848-6666.

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