Andes.
First published in the journal of his Bengal Asiatic Society and then widely reported in Europe, Colebrooke’s findings caused a minor sensation. But they came up against a certain indifference to all things Indian and were not readily accepted. Armchair scholars, inured to absurd claims from the land of rope-tricks and reincarnation, pooh-poohed these tall tales from the hills. Even recognised authorities with some experience of the Himalayas were not readily convinced. Henry Colebrooke seemed to have overstated his case, to have protested too much. High as they undoubtedly were, the Himalayas were too inaccessible and mountain surveying too approximate to justify his sweeping conclusions.
The most disparaging notice came from the most influential publication. In the Quarterly Review , a magisterial journal which until the foundation of London’s Royal Geographical Society monitored the course of discovery, an anonymous but highly competent reviewer found Colebrooke’s paper ‘most curious’. He had no complaint about Colebrooke’s methods or his mathematics but, dealing in turn with each of his cited examples, he demolished them one by one. Crawford’s Nepal observations were ‘of very little value’ because his bearings, distances and triangles were unknown. Robert Colebrooke never got nearer than ninety miles to any of his measuredpeaks, nor did Webb to Dhaulagiri, and nor had Henry Colebrooke at Purnia. Even assuming that the supposed distances were nevertheless correct, the observed angles of elevation, typically about one to three degrees above the horizontal, were too small for confidence. For every error of one second of one minute of a degree (so 1/360th of a degree) in either the instrument or the observation, fifty feet would be added to or subtracted from the supposed height.
And then there was the problem of refraction. The table of allowances which Robert Colebrooke had used was deduced from astronomical observations. It was never intended for terrestrial observations at such low angles over such long distances. The Quarterly Review ’s contributor went into this problem in some detail. Peering out across the English Channel the people of Dover could sometimes see the houses of Calais standing proud of the sea, and at other times, when the atmosphere was equally clear, they could not see them at all. Whale fishers moored off Greenland had noticed the same phenomenon, with snow cliffs appearing and disappearing above the horizon according to the state of the weather and the position of the ice. The whalers called it ‘ice-blink’ and reckoned that objects thirty miles ‘beyond the limit of direct vision’ could yet be clearly seen when conditions were favourable. Temperature, humidity and even the time of the day all seemed to affect the amount of refraction, and in one case it had been found to increase angles of observation by over four degrees. Given that in India the difference of temperature between points of observation in the plains and the ice-encrusted pinnacles protruding above the clouds might be a good 100 degrees Fahrenheit, the properties of refraction could only be guessed at.
In short, Colebrooke’s advocacy was fatally flawed. His facts were ‘insufficient’, his data ‘incorrect’, his conclusions ‘hasty’. ‘On every consideration therefore,’ intoned the Review , ‘we conceive that we are borne out in concluding that the heightof the Himalaya mountains has not yet been determined with sufficient accuracy to assert their superiority over the Cordilleras of the Andes.’
Colebrooke’s response, if any, is not known. But already Webb and a younger generation of surveyors were addressing these criticisms with fierce determination. Their professional competence had been questioned and the honour of their service was at stake. New measurements were being attempted from much more favourable locations, and new proofs would soon be adduced. For by the time that the
First published in the journal of his Bengal Asiatic Society and then widely reported in Europe, Colebrooke’s findings caused a minor sensation. But they came up against a certain indifference to all things Indian and were not readily accepted. Armchair scholars, inured to absurd claims from the land of rope-tricks and reincarnation, pooh-poohed these tall tales from the hills. Even recognised authorities with some experience of the Himalayas were not readily convinced. Henry Colebrooke seemed to have overstated his case, to have protested too much. High as they undoubtedly were, the Himalayas were too inaccessible and mountain surveying too approximate to justify his sweeping conclusions.
The most disparaging notice came from the most influential publication. In the Quarterly Review , a magisterial journal which until the foundation of London’s Royal Geographical Society monitored the course of discovery, an anonymous but highly competent reviewer found Colebrooke’s paper ‘most curious’. He had no complaint about Colebrooke’s methods or his mathematics but, dealing in turn with each of his cited examples, he demolished them one by one. Crawford’s Nepal observations were ‘of very little value’ because his bearings, distances and triangles were unknown. Robert Colebrooke never got nearer than ninety miles to any of his measuredpeaks, nor did Webb to Dhaulagiri, and nor had Henry Colebrooke at Purnia. Even assuming that the supposed distances were nevertheless correct, the observed angles of elevation, typically about one to three degrees above the horizontal, were too small for confidence. For every error of one second of one minute of a degree (so 1/360th of a degree) in either the instrument or the observation, fifty feet would be added to or subtracted from the supposed height.
And then there was the problem of refraction. The table of allowances which Robert Colebrooke had used was deduced from astronomical observations. It was never intended for terrestrial observations at such low angles over such long distances. The Quarterly Review ’s contributor went into this problem in some detail. Peering out across the English Channel the people of Dover could sometimes see the houses of Calais standing proud of the sea, and at other times, when the atmosphere was equally clear, they could not see them at all. Whale fishers moored off Greenland had noticed the same phenomenon, with snow cliffs appearing and disappearing above the horizon according to the state of the weather and the position of the ice. The whalers called it ‘ice-blink’ and reckoned that objects thirty miles ‘beyond the limit of direct vision’ could yet be clearly seen when conditions were favourable. Temperature, humidity and even the time of the day all seemed to affect the amount of refraction, and in one case it had been found to increase angles of observation by over four degrees. Given that in India the difference of temperature between points of observation in the plains and the ice-encrusted pinnacles protruding above the clouds might be a good 100 degrees Fahrenheit, the properties of refraction could only be guessed at.
In short, Colebrooke’s advocacy was fatally flawed. His facts were ‘insufficient’, his data ‘incorrect’, his conclusions ‘hasty’. ‘On every consideration therefore,’ intoned the Review , ‘we conceive that we are borne out in concluding that the heightof the Himalaya mountains has not yet been determined with sufficient accuracy to assert their superiority over the Cordilleras of the Andes.’
Colebrooke’s response, if any, is not known. But already Webb and a younger generation of surveyors were addressing these criticisms with fierce determination. Their professional competence had been questioned and the honour of their service was at stake. New measurements were being attempted from much more favourable locations, and new proofs would soon be adduced. For by the time that the
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