Iodine sublimes.

Crystals of iodine taken in a test tube would sublime at room temperature; they’d pass directly from the solid state to the gaseous state. A purple waft is all that remains. For a while.


We all live in the sublime. Where else can we live? That is the only place of life.

… All that happens to us is divinely great, and we are always in the centre of a great world. But we must accustom ourselves to live like an angel who has just sprung to life, like a woman who loves, or a man on the point of death. If you knew that you were going to die to-night, or merely that you would have to go away and never return, would you, looking upon men and things for the last time, see them in the same light that you have hitherto seen them? Would you not love as you never yet have loved?”

― Maurice Maeterlinck, The Treasure of the humble

Philosopher’s Wool and a Walk Down Chemistry Lane

Zinc oxide is philosopher’s wool. It is formed when zinc burns in air. The white fumes that form as a result of this burning produce a wool like substance, earning it the epithet – philosopher’s wool.

I went on Google Books to find some early references of the oxide, and what I found thrilled me.

The first is a treatise titled Chemical Instructor: Presenting a Familiar Method of Teaching the Chemical Principles and Operations of the Most Practical Utility to Farmers, Mechanics, Housekeepers and Physicians and Most Interesting to Clergymen and Lawyers. Intended for Schools and Popular Class-room by Amos Eaton. This was published in 1822. Eaton famously co-founded the Rensselaer School for ‘the application of science to the common purposes of life’ and was an advocate for the inclusion of women in science.

The following is an image from his treatise on Google Books describing the classroom demonstration of the preparation of philosopher’s wool.


And the following are two rather telling highlights from the Preface of the same treatise.

Here’s another book titled Chemical experiments : illustrating the theory, practice, and application of the science of chemistry, and containing the properties, uses, manufacture, purification, and analysis of all inorganic substances : with numerous engravings of apparatus, etc. by G. Francis. This was published in 1842.

The very first paragraph of the Preface here reads:

The Chemist and Druggist will find in this small book the best method of manufacturing every chemical substance which he is likely to want. The Lecturer will recognize the most remarkable properties of them all, clearly pointed out by such experiments as are easy and striking. The Student will be able to refer to and to repeat the experiments of the classroom with facility. The Manufacturer will find the economical principles of his trade illustrated and the best receipts for his articles given. While he who seeks amusement only will have a wide field before him, from which he may cull the choicest flowers; and should his means be limited, or his residence remote from cities, still little impediment will arise on this account, as one portion of the book assists the other; one experiment explains the manufacture of that substance of which other experiments explain the nature.

Sample this first page from the Introduction chapter which talks of chemistry in those days, which was a part of Natural Philosophy.

And here’s the combustion of zinc described in the form of a laboratory experiment rather than as a demonstration in the previous treatise.

Reading such texts, how can one miss the romantic appeal of chemistry? I hope more and more chemistry (science) educators take it upon themselves to incorporate such examples from the history of chemistry (science) to enthuse students towards the subject, and to inculcate in them an understanding and appreciation of the development of the subject.

PS. Here’s a poem by Brian Culhane titled Philosopher’s Wool from Able Muse, Winter 2009 issue.

Images from Google Books and

C. P. Snow divides. Sir Beaufort sails. And I jut in House’s cane.*

There are times when C. P. Snow’s Two Cultures divide seems redundant. This is one of those times.

I happened to chance upon a piece on the internet titled The Most Exciting Poem Ever Written is The Beaufort Wind Scale. And needless to say, the title reeled me in.

So no, The Most Exciting Poem… is not a poem, but a scientific system of measurement that relates wind speeds to conditions observed on land and sea. The eponymous scale is named after Rear Admiral Sir Francis Beaufort (1774-1857) of the Royal Navy.

The scale defines with economy and precision 13 gradations of wind forces. (Beaufort 0: “calm, smoke rises vertically”. Beaufort 9: “strong gale, chimney pots and slates removed”.) And when I say economy, I am referring to 110 words. I find this amazing! In giving this scale to seafarers (and land-dwellers), Sir Beaufort offers us a peep into his mind. And what I find in there, over and above all, is grace in abundance.

So, here’s the scale as posted by Mallory Ortberg on The Toast. Good writing moves, they say. And I admit I am moved. (I might be in an altogether new orbit of earth as I write this.)

Description on Land | Description at Sea

Calm: Smoke rises vertically. | Sea like a mirror.

Light: Wind felt on face; leaves rustle; ordinary vanes moved by wind. | Small wavelets, ripples formed but do not break: A glassy appearance maintained.

Moderate: Raises dust and loose paper; small branches begin to move. | Small waves with breaking crests. Frequent whitecaps.

Fresh: Small trees in leaf begin to sway; crested wavelets form on inland waters. | Moderate waves, taking a more pronounced long form; many white horses are formed – a chance of spray.

Strong: Large branches in motion; whistling heard in telephone wires; umbrellas used with difficulty. | Large waves begin to form; the white foam crests are more extensive with probably some spray.

Near-gale: Whole trees in motion. Effort needed to walk against the wind. | Sea heaps up and white foam from breaking waves begins to be blown in streaks along direction of wind.

Gale: Twigs break off trees; progress generally impeded. | Moderately high waves of greater length; edges of crests begin to break into spindrift; foam is blown in well-marked streaks along the direction of the wind.

Strong gale: Slight structural damage occurs – roofing dislodged; larger branches break off. | High waves; dense streaks of foam; crests of waves begin to topple, tumble and roll over; spray may affect visibility.

Storm: Trees uprooted; considerable structural damage. | Very high waves with long overhanging crests; the resulting foam in great patches is blown in dense white streaks; the surface of the sea takes on a white appearance; the tumbling of the sea becomes heavy.

Violent storm: Very rarely experienced – widespread damage. | Exceptionally high waves; small and medium sized ships occasionally lost from view behind waves; the sea is completely covered with long white patches of foam; the edges of wave crests are blown into froth.

Hurricane: Very rarely experienced – widespread damage | The air is filled with foam. Sea completely white with driving spray.

Here’s the scale with the Beaufort Numbers and wind speed classification.



And this: Scott Huller has written a book on this very scale. It is called Defining the Wind. I haven’t yet read it, but going by the excerpt that he provides on his blog, I am sure I’ll soon be getting my hands on it.

As I finish this post, there’s House on my mind. Perhaps due to the C. P. Snow divide that I began with. To paraphrase House completely out of context (where else could I do this, if not on here?): There is no Great Wall of China with armed sentries posted every 20 feet between Science and Humanities. There is just a sometimes-here-sometimes-not thin line between them.

*And yes, there’s a glaring anachronism (not to mention, the hyperbole) in the post’s title. But then, writing is a free country. And so it grows.

Of a picture that spoke a million words. And, a book reco.

The Mars Orbiter Mission aka the Mangalyan was launched about an year back. It was a proud and happy moment for all of India. Soon after the space probe’s launch, the internet became abuzz with the picture of ISRO women scientists congratulating themselves on the launch. That picture made me jump for joy. And I diligently spread the joy around by sharing the picture with anyone who’d care to lend an eye and an ear.. And because joyous things need to be shared again and again, here’s the picture for your viewing pleasure.

This is rocket science!

Yes, this is rocket science!

I remember sharing this picture with my class, and my students were all taken by the magnitude of achievement these pixels contained.

Truly Lilavati’s daughters, these women.

Which brings me to the second part of this post. This is actually a book recommendation, and the name of the book is Lilavati’s Daughters: The Women Scientists of India. The latter part of the title is self-explanatory; the book is an anthology of biographical essays by leading women scientists in India. As for the first part of the title, my understanding is that Lilavati was the Indian mathematician, Bhaskara’s daughter. Legend has it that Lilavati was a very intelligent woman and that she did not have any children of her own. The lore further has it that Bhaskara, like all fathers wanted to get his daughter married, but couldn’t. And so, to assuage the pain caused by his inability to do so, he promised his daughter to write a book in her name. This Wikipedia page carries the historical background on Lilavati, the treatise written by Bhaskara for his daughter. An English translation of the book is available here. Wikipedia’s outgoing link to Google Books also delivers.

Right. So, back to why I began this post: the anthology of essays by women scientists. It is available in its entirety here as downloadable pdf chapters. Go on, read it. Just don’t complain if your mind begins to expand as you come to know of the vast pantheon of courageous and intelligent women you have as your forbears.