Manchester | July 19th 1854.
Sir,
At the request of my friend Mr Hopkins of Cambridge, I have forwarded specimens1 of substances 3/102 of an inch square – compressed under pressures, some of them to the extent of nearly 80,000 lbs on the square inch. You will find two specimens of each kind and I trust of such dimensions as will enable you to ascertain with considerable accuracy the conducting powers of the different substances which Mr Hopkins desired me to submit to experiment.
It will afford me much gratification if you will kindly furnish me with a copy of your results,3 and if not asking too much, I should at the same time be glad to have the specific gravity of each. I am desirous of having these results for other objects than those contemplated by Mr Hopkins, and I shall esteem it a favour if these objects can be accomplished without inconvenience.
I am, Dear Sir | yours faithfully4
Dr. Tyndall | &c. &c.
RI MS JT/1/TYP/2/609
LT Typescript Only
specimens: on 12 June Hopkins referred to a ‘supply of specimens’ that he was hoping to send to Tyndall from Manchester (see letter 0938, n. 3).
3/10: the number 10 is partially handwritten and covering an illegible, typed character, suggesting that LT corrected a typographical error.
your results: Hopkins wanted Tyndall to experiment on the conductive powers of the specimens (see letters 0929 and 0938).
yours faithfully: the typescript did not include a signature.
Please cite as “Tyndall0955,” in Ɛpsilon: The John Tyndall Collection accessed on