Warren De La Rue to Faraday   6 July 1849

No. 7 St. Mary’s Road Canonbury | July 6th 1849

My dear Sir

This is a begging letter - if not convenient to you to comply with my request lay it on one side and do not trouble yourself any more about it. I apply to you on behalf of a worthy man judging by his works and acts - a Mr. Nobert of Greifswald in Pomerania - a maker of microscopes and other philosophical instruments - he says “I have already asked so much & yet, cannot refrain from enquiring whether you could procure from Mr. Faraday a piece of his heavy glass”[.]

The applicant has accomplished, at my suggestion, some dividing on glass of such extreme fineness that it is a question whether the physical properties of light do not prevent our resolving it - the divisions being about the one hundred & ten thousandths of an inch apart from centre to centre and therefore considerably less than the wave-length of even the violet ray.

I have but just received the specimen and have not yet examined it but it will I have little doubt serve to elucidate some of the properties of light - it is a mechanical wonder at any rate and reflects the highest credit on the patience and skill of Mr Nobert. This is the man who wishes for a bit of your glass. I do not think that it will be lost on him if you have it to spare - but I am quite aware that these applications have been repeatedly made since you terminated your experiments¹ and shall therefore not be at all surprised to learn that this comes too late.

Yours Very truly | Warren de la Rue

Michael Faraday Esq | &c &c &c