Eliza de Feuillide ,Janes cousin, took her poorly son to sea bathe and was convinced of the benefits;

"I had fixed on going to London the end of this Month, but to shew You how much I am attached to my maternal duties, on being told by one of the faculty whose Skill I have much opinion of that one month’s bathing at this time of the Year was more efficacious than six at any other & that consequently my little Boy would receive the utmost benefit from my prolonging my stay here beyond the time proposed, like a most exemplary parent I resolved on foregoing the fascinating delights of the great City for one month longer ... Was not this heroic? … Hastings grows much & begins to lisp english tolerably well, his education is likewise begun, his Grandmamma having succeeded in teaching him his letters. The Sea has strengthened him wonderfully & I think has likewise been of great service to myself, I still continue bathing notwithstanding the severity of the Weather & Frost & Snow which is I think somewhat courageous"

This was a letter sent from the seaside resort of Margate on the Kent coast from Eliza to Philadephia Hancock, her cousin,dated 7th January 1971.

Frankly she was braver than I could ever have been!

Fanny Bruney also mentions sea bathing in her Dairy and letters;in particular she makes this refernce to teh "dippers";dippers or guides were an essential accompaniment to the bathing machines.

The bathing-machines make it [‘God Save the King’] their motto over all their windows; and those bathers that belong to the royal dippers wear it in bandeaus on their bonnets, to go into the sea; and have it again, in large letters, round their waists, to encounter the waves. Flannel dresses, tucked up, and no shoes or stockings, with bandeaus and girdles, have a most singular appearance; and when first I surveyed these loyal nymphs it was with some difficulty I kept my features in order.

Nor is this all. Think but of the surprise of His Majesty when, the first time of his bathing, he had no sooner popped his royal head under water than a band of music, concealed in a neighbouring machine, struck up ‘God save great George our King’.

The dippers were mainly local women and some men who escorted their customers into the water and dipped them. As the bather emerged from the machine the dipper ensured they were immersed deeply enough and then dipped them into the oncoming waves or, if the sea was calm, pushed their heads under water.

For medically prescribed bathing the standard dip was apparently three total immersions, and this number can probably be traced back to early Christian baptisms where adults were immersed in water and dipped under it three times.