Faraday to Jacob Herbert   27 April 1854

Royal Institution | 27 April 1854

My dear Sir

I beg to report to you upon the two waters received from the Skerries¹; in reference especially to the probability that ill health may have been the result of their use by the lighthouse keepers. The supposition is, that a poisoning, as by lead, has been produced by them: but there is not the slightest chance of such an effect from waters in the state of those received by me. The two specimens were distinguished as tank water and Cottage water. Both poured out perfectly clear from the bottles and neither contained a trace of lead. They contained small portions of saline matter: that labled Tank the least: the salts in it were a little sulphate of lime and a larger proportion of common salt, the latter probably derived from sea spray - both in wholesome proportions. The Cottage water contained the same substances with a little carbonate of lime and the common salt was in larger proportion than before still the water was good.

In both these bottles I could find at the bottom a very small portion of settled matter; and in that labled Tank the deposit contained a trace of lead. In that from the Cottage there was no signs of it. Whether the lead was in solution in the Tank water when put into the bottle, or whether it had been drawn up from a deposit in the tank by the pump I cannot say. Lead cisterns often contain such deposits & yet the clear water from them is perfectly good & wholesome. If at any given time turbid water had been drawn up from the Tank & used in that state then I could have supposed that it had something to do with the injurious effects described but I do not think the water as it has come to me could produce them.

On one occasion when I was at the Needles lighthouse I found the roof had been painted and that the weather & rain had carried off much of the carbonate of lead; making the roof most ugly and sadly injuring the water for the time for any domestic purpose². Can any thing of this kind have happened at the Skerries and thus have injured the water for a time? If so the ill health would be referable to a given period.

It might perhaps be desirable to supply a filter containing a layer of charcoal or sand or both to the lighthouse[.] If sediment is ever pumped up with the water the filter would retain it & even lead in solution would be taken out. Supposing the water really & always right so that no filter was required still it might have a moral effect & reassure the keepers minds: but then it might also have the contrary effect & frighten them without cause³[.]

I am | My dear Sir | Your Very faithful Servant | M. Faraday

Jacob Herbert Esq | Secretary | &c &c &c