My life : a record of events and opinions - Wallace-online.org

My life : a record of events and opinions - Wallace-online.org My life : a record of events and opinions - Wallace-online.org

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3^4MY LIFEmidway with two discs on it, the upper disc, thetelescope at A, and the black line on the bridge at C,being all exactly the same height above the water.If the surface of the water is truly flat, then on lookingatthe mark C with the telescope A, the top disc Bwill cover that mark.But if the surface of the wateris curved, then the upper disc will appear above theblack mark, and if the disc is more than four feetabove the line joining the telescope and the black^^ it.mark, then the lower disc willalso appear above theblack mark. Before the experiment was made adiagram similar to this was submitted to Mr. Hampden,his referee Mr. Carpenter, and Mr. Walsh, and allthree agreed that it showed clearly what should beseen inthe two cases, while the former declared theirfirm belief that Fig. 2 showed what zvoiUd be seen.When the pole was set up and the mark put uponthe bridge, Mr. Carpenter accompanied me, and sawthattheir heights above the water were the same asthat of the telescope resting on the parapet of thebridge. What was seen in the large telescope was

!I" Signed by Mr, Carpenter."—Z)r. Coulcher's Report. '^SignedMONEY MATTERS 365sketched by Mr. Coulcher and signed by Mr. Carpenteras correct, and is shown in the following diagramwhich was reproduced in the Field newspaper (March26, 1870), and also in a pamphlet by Carpenter himself.But he declared that this proved nothing,because the telescope was not levelled, and because ithad no cross-hairAt his request to have a spirit-level in order toshow if there was any " fall " of the surface of water,I had been to King's Lynn and borrowed a goodTroughton's level from a surveyor there. This I nowset up on the bridge at exactly the same heightabove the water as the other telescope, and havinglevelled it very accurately and called Mr. Carpenterto see that the bubble was truly central and that theleast movement of the screws elevating or depressingit would cause the bubble to move away, I adjustedthe focus on to the distant bridge, showing also thecentral staff and its two discs.Mr. Coulcher looked at it, and then Mr. Carpenter,"

3^4MY LIFEmidway with two discs on it, the upper disc, thetelescope at A, <strong>and</strong> the black line on the bridge at C,being all exactly the same height above the water.If the surface <strong>of</strong> the water is truly flat, then on lookingatthe mark C with the telescope A, the top disc Bwill cover that mark.But if the surface <strong>of</strong> the wateris curved, then the upper disc will appear above theblack mark, <strong>and</strong> if the disc is more than four feetabove the line joining the telescope <strong>and</strong> the black^^ it.mark, then the lower disc willalso appear above theblack mark. Before the experiment was made adiagram similar to this was submitted to Mr. Hampden,his referee Mr. Carpenter, <strong>and</strong> Mr. Walsh, <strong>and</strong> allthree agreed that it showed clearly what should beseen inthe two cases, while the former declared theirfirm belief that Fig. 2 showed what zvoiUd be seen.When the pole was set up <strong>and</strong> the mark put uponthe bridge, Mr. Carpenter accompanied me, <strong>and</strong> sawthattheir heights above the water were the same asthat <strong>of</strong> the telescope resting on the parapet <strong>of</strong> thebridge. What was seen in the large telescope was

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