Brilliant Women: 18th Century Bluestockings, National Portrait Gallery, London

Brilliant women, boring show

I walked into this exhibition blithe of heart. It was clearly a good idea whose time had come: to explore the roles of various extremely clever – many of them aristocratic – women in the second half of the 18th and the early decades of the 19th century; to demonstrate how they had made their mark in the fields of education, science, social and political activism. To examine how one particular grouping, somewhat aping those famous French salons presided over by the likes of Madame de Pompadour, had called itself the Bluestocking Club.

And what did this group get up to? It was dedicated to the arts of enlightened conversation, which would doubtless have encompassed literary criticism, classical scholarship, the nature and status of women and their education, and much else. And then, finally, to see those same brilliant, proto-feminist ideals go into steep decline as the Peninsular Wars sapped at the confidence of English society, and led to a backlash, and an increasing belief that women, after all, were fit for nothing but the nursery. So Bluestocking, which had at first been a word of praise, survived – and continues to survive to this day – as a term of opprobrium.

Unfortunately, life – and exhibitions – are not always quite as good as a quick summary of the marvellous idea that has brought them into being suggest that they might be and, as I walked through the exhibition, examining, one by one, the portraits of hostess Elizabeth Montagu, novelist and diarist Fanny Burney, and painter Hester Chapone (one of just two female painters who were elected to the newly established Royal Academy), the last few words of a great 18th-century poem, Alexander Pope's "Dunciad", began to seep into my mind. And what were those words? "And universal darkness buried all."

The sad truth is that, in spite of the fact that these women achieved so much, their portraits are, with very few exceptions, as dull as dishwater. The bottle has simply not captured the spirit of their brilliance. The fact is that these women were competing in a world of largely unsympathetic men, and these portraits, in general, are overburdened by the kind of gravitas that would prove them to be the equal of all those sneering males such as William Hazlitt, who once wrote: "I have an utter aversion to Bluestockings. I do not care a fig for any woman that knows even what an author means."

There is very little that lives and breathes in these portraits. What we generally see are masks, allegorical personages, dully conventional representations of cultural sophistication. We seldom glimpse the person beneath this dreary decorum, respectability and bland classicising. There are other problems, too. There is at least one portrait that might have been here, and that is, inexplicably, absent. We see a small print of Reynolds' great portrait of the actress Mrs Siddons, for example. Why in heaven's name can we not see the portrait itself? That would have raised the quality of the exhibition at a stroke.

The great exception is the portrait of the woman who was the most violently controversial figure of them all, Mary Wollstonecraft. In the magnificent portrait by John Opie, we feel that we are at last engaging with an awkward, charged, eager, opinionated human presence. There are no aristocratic or classical props to help her along her way up the shining hill to Parnassus, merely the slightly unkempt and unruly presence of a woman who stares at us side-on.

How wonderful to see a real person after such a train of stuffed goddesses. And just a little way away from that portrait, there is a letter, written in her own strong, open, generous hand to the historian Catharine Macaulay, in which she says: "I respect Mrs Macaulay... because she contends for laurels whilst most of her sex only seeks for flowers."

Yes! we say to ourselves as we read those pugnacious words, now there, finally, is evidence of a real spirit of bold defiance, and one who would happily have gone the full 15 rounds with that sad, sneery Hazlitt.

To 15 June (020-7312 2463)