and there is the potential for individual exploration within this confmed range, hut there are no "bells and whistles" or other attention-grabbing incentives for digging out underlyingrelationshim. Student reaction has been. That's neat. but so what? Obvinuslv. .. this oroeram needs some imorovement.. most importantly an error rrnp tu at lrnst warn thr user of a potentla1 prublcm The inability ol'thc prohTam to run under MULTIFISI)ER was known t,, thccompany, but rherr was no mention ofthls problem either in the operation of the program or in the manual. The scaling prohlem could easily have been missed in trials, hut rhere shouldhe some type of &or trap to avoid a cumpletr crash In any such unforcscen event There should also be a fneilny fur KES'PARTTNG the machine w t h the disk in oincc. With these operational features corrected,'there is still considerable room for improvement. The inability to print tables directly is a nagging limitation that should not appear in software in this price range. The inability to re-sort and rearrange columns in the tahle without starting completely aver is also irritating. If very many properties are to he listed in the table, a listing of the properties selected and their order would be helpful, a s would a facility to add or delete choices. There could potentially be some benefit to adding a facility for performing mathematical manipulations (in addition to logarithms) on properties, such as the ratio of one property to another, before creating a table or graph. The ability to set upper and lower limits on the XandY axes ofXY plots would also be of value. In summary, MacMendeleev appears to be a n excellent resource for teachine oeriodicitv. maohic ,. with the ahilitv to oroduce some .. lecture a d s Thl* prudumon could be expandcd toa broader range of lecture n d s s,lrh a few additional program modules Without these additinnr, and pnrtirulurly with the existing ghtchcs, this program is seriously overpriced. ~~~
~
.
~~~~
~~~
~
~~~~~
.~~-
~
~
~~~~~
.- .
. .
.
Gary L. Bertrand University of Missouri-Rolla Rolla. MO 65401
program. If the ranges of the three variahles are platted as a box in three-dimensional Cartesian coordinates, the variable combinations chosen hy the program are the centers of the 12 box edges and the center ofthe box. The variables correspandingto the center actuallv of the box are to be used three times. so that the oramam . suggests I5 e x p e n m a t s Whcn there arc four independent varal t o n r or sbles, 25 qrts of variables are pnwidrd by the pn,h~,l-ant. mow ofthe combination.i ofvar~ablrssug~wstcdby the program rs not feasihle, perhaps the reagents precipitate a t one of the pH values suggested, another set of variables may he entered hy the user. Once the ex~erimentshave been performed and results ohtained, a n ~ t h e ; ~ r a g r a m will accept these results, calledrespanses by the program, along with the actual values of the variahles used. At this noint.. the software can evaluate a 'model'., essentiallv a n eouationfor the deoendenceoftheexnerimental result ontheinnut ,~ , vnriablt*. In the tutonal thnt comes wlth thc software, a iuil second-ordcr pol>numinl with arbitrary ronstnnts is used and nll theconstants arc cvnlunted along wirh thrperrcnt confidencethat each constant is significantly different from zero. The program can then be used tocalculate thepredietedresultfromeach experiment using this model, and then calculates residuals. The software can then~alsomake plots of the anticipated results for various comhinations of the inhependent variables using this model. An advanced eraduate student used this software to examine somedata involwng three i n d c p m d ~ nvariablri t where thecorrect equation connecting the vnnahles to the expenmental results was k n w n to be very dimerent frurn n second-order polynomial. The second-order polynomial and another arbitrary equation involving the square roots of two of the variables and the logarithm of the third were presented to the program with undetermined coefficients. As might he expected, large residuals were obtained far some of the data. Also as expected, the program gave very small residuals when the correct equation was used. Unfortunately, there is no way in which this software can he used to give guidance to the user about the correct equation to he used except by careful examination of the results, especially the residuals, using equations whose form is alreadv known. This software nackaw ,. oroha, hly ~ v c hcst s results H hen the drpendencr of the experimcntnl results on the mdrpcndrnt varrablcs is rrlnrively simplc T h i suftwsrc package appcaarz to be extremely specialized and P U T P O S ~ S . It could roneewahly be used not meant for p~dago~
