Letters

Elementary problem

I read the article, Elementary order (Down To Earth, January 15, 1995), in which certain facts have not been presented properly.

The Periodic Table is the long form, also called the Modern Periodic Table and not the Mendeleev (and certainly not the Medekeyev) Periodic table, and is incompelete without numbering the columns in it. There is mention of the Modern Periodic Table in the text. The accepted IUPAC recommendation says that 18 columns be numbered from 1 to 18 and the earlier notataion of 1a, 1b, IIa, IIb, etc, be given up.

The IUPAC Commission on the Nomenclature of the Inorganic laid down a procedure to name the elements with atomic numbers greater than 104. The names are composed of the these roots representing digits of the atomic number: 1 un 2 bi 3 tri 4 quad 5 pent 6 hex 7 sept 8 oct 9 enn 0 nil.

The ending -ium is then added to the 3 roots. The 3 letter symbols are derived from the letters of the coressponding roots.

P S SINDHU
New Delhi

The Periodic Table presented is indeed the Modern Periodic Table and the article ends with a reference to it. However, the term "modern" in the caption for the picture and the numbering of columns were inadvertently left out .

Further, Mendeleyev'e name is spelt both ways -- Mendeleyev as well as Mendeleev -- and the former is used in the Encyclopaedia Brittanica. As for the names and symbols referred to by P S Sindhu for elements 101-110, they are old and the IUPAC has given them new names, which really is the root of the controversy mentioned in the article. Their complete names were given in the article as their exact abbreviations or symbols are not yet available. ...

Wrong spots

In the February 15, 1995 issue of Down To Earth, I was amazed to find the news item on cheetah deaths in the Delhi Zoo accompanied by a picture of a leopard! The extinction of the cheetah from the Indian region remains under-appreciated even almost half a century after the fact -- and leopards continue to be confused with cheetahs by large sections of the Indian press. I hope you will avoid such mistakes in future from your otherwise excellent magazine.

MADHUSUDAN KATTI
Tamil Nadu - 627 551

The error is regrated. ...

Chocking on ozone

Putting the brakes on emissions (September 15, 1994) reports on the decision of the state government of Hesse in Germany to introduce a temporary speed limit on its autobahns. But contrary to what your article says, it is not the ozone-depleting gases produced by traffic which prompted the government's decision, but it is the ozone-producing gases.

I have been to germany this year to witness an extraordinary hot summer. In strong sunlight, exhaust gases from automobiles react with oxygen to form ozone in the atmosphere near ground level. Breathing in ozone causes headaches and breathing problems, which is why the authorities advised children and old people to stay indoors.

Hesse is one of the few states in Germany to install safety limits of ozone concentration in the air of 180 parts per million. As the limit was crossed all over, the Hesse government, ruled by a coalition of Social Democrats and the Green Party, imposed a speed limit, which was surprisingly observed by most car drivers.

Germany is perhaps the last country in the world which has no general speed limit on its highways. The ruling party Christian Democratic Union praises itself to uphold the freedom of fast movement, that is why it is not in favour of limiting car speeds shortly before important elections. But high speeds of cars does not lead to "fuel burnt less efficiently" as expalined in the artcile but to higher fuel consumption and therefore more pollution.

RAINER HORIG, Germany ...

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