what tools did darwin use to record his observations
Posted by: Rob Viens | February 7, 2012
Tools of the Trade
February 7th was a rare day in which Darwin did not enter anything in his diary. It seems that this became less common as the voyage continued – possibly as he became more disciplined well-nigh keeping a daily tape. Like many days, I doubtable he was analyzing the many samples that he collected on the island.
Analysis of samples in the field in the early on 1800's was conducted in a manner that was not that different how geologists clarify samples today, and Darwin had a full regiment of geology equipment with him on the trip.
First and foremost, he couldn't call himself a geologist without a rock hammer for breaking through the weathered surface of a rock to see its true nature. I was thrilled to find that Darwin's rock hammer, the very i that traveled with him on the Beagle, was in the Sedgwick Museum of World Science. Anytime I have to see this in person!
Though I have to say I am amazed it still exists – I think my kickoff rock hammer lasted about 2 years before I lost it in the field. On a higher trip. If Darwin left his hammer in Cape verde or Terra del Fuego, in that location would accept been no going back to observe it afterwards!
In the field Darwin would have as well used his "geological compass" or clinometer (geologists oftentimes refer to this as a "Brunton" or "Brunton Compass" today). The clinometer allows i to accurately describe the orientation (strike and dip) of layers of rock in the field. It can as well serve as a survey tool for triangulating locations and heights.
Darwin's Clinometers from serc.carlton.edu:
Darwin plainly struggled making measurements with a clinometer. Though a few months before the voyage he wrote to his mentor J.S. Henslow to say how he had been practicing with his new toy:
"I should accept written to you one-time ago, only I was adamant to expect for the Clinometer: & I am very glad to say I think it will respond admirably: I put all the tables in my bedroom, at every believable angle & direction I will venture to say I have measured them as accurately every bit any Geologist going could practice." (Correspondence with J.S. Henslow on July 12, 1831)
He seems to spend some fourth dimension in the early on parts of the voyage standing to make sure he was using it correctly. Obviously, the accurate measurements of the Baobab tree in Republic of cape verde where fabricated by Fitzroy, as Darwin may take still been struggling to master the technique. There is some solace in the fact that measuring strike and dip with a Brunton Compass is one of the more difficult concepts for modernistic geology students to master – they were not alone!
Dorsum on board the ship (or in the tent) Darwin could case the samples he collected using several tools designed to help identify minerals. These included a goniometer and a set of blowpipes. Every mineral has a unique chemic composition and chemical structure (arrangement of atoms). This "crystalline structure" is reflected in the outward crystal shape of a mineral. A goniometer allows the mineralogists to accurately mensurate the crystal shape (specifically the angle between the flat planes of the mineral surface). This measurement tin assist in mineral identification.
Contact goniometer from the Virtual Museum of the History of Mineralogy:
A blowpipe was a tool used to measure the other unique characteristic of a mineral – its chemic composition. The user would place a chip of the mineral in a flame and could blow a concentrated stream of oxygen downwards the pipe to "fan the flames". This immune the temperature of the flame to attain upwards of 1500°C. Past "called-for" a specimen at these temperatures, observations of the colour of the flame or the odor produced could assist place the chemical limerick, and thereby help ID the mineral itself.
A blowpipe set in its case and in use from Virtual Museum of the History of Mineralogy:
In Geological observations on the volcanic islands visited during the voyage of H.M.South. Beagle, Darwin refers to measurements fabricated with the blowpipe frequently, including this one from Cape Verde:
"This earthy affair is of a pale yellowish-brown colour, and appears to be a mixture of carbonate of lime with iron; it effervesces with acids, is infusible, just blackens under the blow-pipe, and becomes magnetic."
Notice Darwin also refers to the geologists trusty "acid examination" – testing a mineral composition based on whether or non information technology reacts with acid. This makes carbonate minerals easy to identify.
Finally, existence able to look at rocks (and biological samples) under magnification allowed for detailed descriptions and was often helpful for identification. Therefore, no traveling naturalist (Darwin included) would be without a microscope. Darwin's would have looked much similar this one, from the Whipple Museum of the History of Science:
Of course, all the tools in the world don't assist you if you don't know how to make careful observations of the world and record them in a manner that makes sense to other scientists. This was Darwin's true strength and I'll come back to that in the side by side couple of days.
For more info come across the Sedgwick Museum for a neat interactive site that shows how to utilize 19th century geologic tools. (RJV)
Source: https://beagleproject.wordpress.com/2012/02/07/tools-of-the-trade/#:~:text=In%20the%20field%20Darwin%20would,of%20rock%20in%20the%20field.
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