The modernist writer Virginia Woolf called letter writing "the humane art, which owes its origins in the love of friends". In our frenetic world of electronic communication, we must remember to write with thought and consideration, says historian Lisa Jardine.

In these days of email, texts and instant messaging, I am not alone, I feel sure, in mourning the demise of the old-fashioned handwritten letter. Exchanges of letters capture nuances of shared thought and feeling to which their electronic replacements simply cannot do justice. Here's an example.

In July 1940, with the country at war, Virginia Woolf published a biography of the artist, Roger Fry - champion of post-impressionism and leading member of the Bloomsbury Group. The timing could hardly have been worse. Fry's reputation was as an ivory tower liberal who believed that art inhabits a self-contained formal space remote from the vulgar world. As France fell to Hitler's troops and German planes pounded the south coast of England with increasingly regular air-raids, such artistic idealism seemed at best out of touch, at worst irrelevant.

Most of Woolf's friends were politely positive about the book. But in early August she received a letter from Ben Nicolson, the 26-year-old art critic son of her close friend Vita Sackville-West, who was serving as a lance-bombardier in an anti-aircraft battery in Kent under the flight-path of the German bombers. As enemy warplanes passed low overhead, Nicolson attacked the adulatory tone of Woolf's biography and accused Fry of failing to engage with the political realities of the inter-war years.

"I am so struck by the fool's paradise in which he and his friends lived," Nicolson wrote. "He shut himself out from all disagreeable actualities and allowed the spirit of Nazism to grow without taking any steps to check it."

Woolf's answering letter did not mince words:

"Lord, I thought to myself," she wrote back. "Roger shut himself out from disagreeable actualities did he? What can Ben mean? Didn't he spend half his life travelling about England addressing masses of people who'd never looked at a picture and making them see what he saw? And wasn't that the best way of checking Nazism?"

Stung by Woolf's condescending tone, and unpersuaded by her argument, Nicolson wrote again, criticising Fry and the Bloomsbury Group in yet stronger terms. This time Woolf took his comments personally and drafted a lengthy, rebarbative reply, in which she turned Nicolson's attack on Fry and herself back on him. Nicolson's own chosen career as art critic was hardly more engaged: "I suppose I'm being obtuse but I can't find your answer in your letter, how it is that you are going to change the attitudes of the mass of people by remaining an art critic."

Reading over what she had written, however, Woolf thought better of her stern tone and did not send the letter. Instead, she rewrote it in more measured terms, moderating her sharp remarks with an opening apology. "I think it's extraordinarily nice of you to write to me," she now began, "I hope I didn't annoy you by what I said. It's very difficult when one writes letters in a hurry as I always do, not to make them sound abrupt."

It is this second version of the letter that was eventually dispatched, and which evidently satisfied its recipient, who called a truce on their differing views of Fry's influence and reputation. In early September, Woolf wrote to arrange for Nicolson to visit, adding: "I love getting your letters," and "I'm so happy you found the life of Roger Fry interesting as well as infuriating."

Two things strike me in this exchange. The first is the simple good manners both correspondents evidence in the way they address one another and present their arguments, in spite of the real, keenly felt differences of opinion.

Image caption Virginia Woolf understood the effects of letters written in haste

The second is the strikingly different outcome arrived at because Virginia Woolf restrained herself from dispatching her first, intemperate draft reply and carefully modified it so as not to hurt the feelings of the young man - a family friend, very much younger and less experienced than herself.

I have, of course, dwelt on this exchange for a purpose. In it, Woolf - using established letter-writing conventions - takes advantage of the time lapses between exchanges to recuperate, clarify, recast and take control of the argument. The result has the elegance of a formal dance - a kind of minuet, in which the participants advance and retreat according to well-understood rules, until they have arrived at a satisfactory outcome.

How unlike the rapid firing off and counter-fire of email messages in which many of us find ourselves engaged nowadays as our predominant means of communicating with colleagues and friends, and even with complete strangers. Each time I broadcast a Point of View, I receive large numbers of emails from people I have never met, while the script posted on the BBC magazine website generates hundreds of anonymous messages.

Very few of these observe the courtesies enshrined in traditional letter-writing. Many adopt a curiously curt tone: I have not consulted my sources correctly, they insist, or I have misled my listeners. "Call yourself a historian" is a regular, shrill opener - emails and posts have mostly dispensed with the niceties of "Dear Lisa" or "Yours sincerely."

Yet if I answer such an email - and I do try to respond to them all - the reply that follows will be couched in very different terms. It will be prefaced by the kind of placatory remark Woolf used in responding to Nicolson: "I did not mean to imply criticism" or "I hope you did not think me rude." It is as if between the first and the second response I have become a person - an actual recipient of the communication - rather than an impersonal post box. So the courtesy and simple good manners of more old-fashioned letter-forms are restored to our correspondence.

Image caption Emails have replaced the handwritten letter

The most dramatic feature of electronic communication is surely its propensity to tempt us into dashing off a message in haste that we repent at leisure. As the emails ping into our inbox we answer them helter-skelter, breathlessly, without pausing to reflect on nuance or tone. As a consequence, misunderstandings often arise - "I'm sorry to have upset you," a colleague will reply to an email I intended as a matter-of-fact response to a bit of university business.

No doubt I am sentimentalising the orderliness of written letters by comparison with emails. When feelings run high, an ill-judged letter can cause as much emotional damage as any dashed-off online posting. Here's another example from Virginia Woolf's prolific correspondence.

In 1938, she wrote to Vita Sackville-West - with whom she had had a passionate affair in the late 1920s - refusing to read a poem Vita had sent her via Woolf's husband Leonard. Woolf was annoyed at hurtful remarks Vita had made about her:

"Leonard says you have sent a poem and would like to know what I think of it. Now I would like to read it and normally would fire off an opinion with my usual audacity. But I feel I can't read your poem impartially while your charges against me, as expressed in a letter I have somewhere but won't quote, remain unsubstantiated."

Image caption Vita Sackville-West was 'horrified' by one of Woolf's letters

Vita was appalled. Her response was a frantic telegram: "Horrified by your letter." This in its turn elicited a further letter from Woolf the same day:

"What on earth can I have said in my letter to call forth your telegram? God knows. I scribbled it off in five minutes, never read it through, and can only remember that it was written in a vein of obvious humorous extravagance and in a tearing hurry."

Woolf explained that she had been annoyed by a letter Vita had sent shortly after publication of her last book. She had written back asking Vita to explain a comment she had made that "one moment you enchant with your lovely prose and the next moment exasperate one with your misleading arguments". What were the misleading arguments? Woolf had asked. Vita had not replied.

"It's a lesson not to write letters," Woolf now continued contritely. "For I suppose you'll say, when you read what I've quoted from your own letter, that there's nothing to cause even a momentary irritation. And I daresay you're right. So let us leave it: and I apologise and will never write a letter so carelessly again."

Virginia Woolf called letter-writing "the humane art, which owes its origins to the love of friends", and devoted a good deal of emotional energy to using it to maintain her friendships.

Today's electronic forms of communication may lack that emotional depth but they do enable us to connect more speedily and efficiently than I at least could manage with pen and ink. Still, when we take advantage of them, we ought always to heed Woolf's warning, never to write carelessly. And, if we can, at least count to 10, and read over what we have written, before we press "send".