In 1790, the United States was only civilized along the eastern shore of the country. Around 1800 civilization started to expand west more and more every decade, in large thanks to the Corps of Discovery. There are many different types of climate and Geographical features across America. The southern climate tends to be humid and hot, with long lasting summers and short, rather mild winters. Most areas of the south see plenty of rainfall, making it a climate perfectly suited for agriculture. The northern half of America tends to be much more balanced with four even seasons (with some exceptions). In the eastern part of the country the Appalachian mountains are probably the most defining landform, reaching from Maine to Georgia. The western half is marked by beautiful landmarks such as the Grand Canyon and the vast Rocky Mountains. America has so many valuable geographical resources in all corners of the country and in between. In 1803 Thomas Jefferson ordered Lewis Meriwether to find the most direct route across the continent to the Pacific Ocean. Lewis chose his close friend, William Clark to be co-commander of this expedition, later known as the Corps of Discovery. The crew of about 30 men set off near St. Louis, Missouri, in may 1804. The expedition through the uncharted American interior faced many hardships and great obstacles. The group reached the Pacific Ocean in November of 1805 and made the long journey back to Washington D.C. They completed the expedition in 1806, travelling roughly 8,000 miles total. As the Corps of Discovery travelled for three years through the Ohio River, up the Missouri River, over the Continental Divide, and to the Pacific Ocean, Lewis served as the crew’s field scientist. He collected very important and detailed geographical information along the journey. The expedition laid the groundworks for geography not just in the west, but for the whole country. They provided extensive facts on the northwest’s natural resources as they documented over 100 animal species and 170 plants. They also studied the minerals, size, and the geology of the area and produced more than 140 maps with the information the team gathered. The expedition brought many mathematical tools with them, such as a surveyor’s compass, quadrants, thermometers, sextants, plotting instruments, chronometers, and telescopes. These tools were critical in laying out the geography of the newly discovered land. Lewis had a refracting terrestrial telescope with an achromatic objective lens, some say it embodied his love for technology. His “spy-glass” was used for important daytime observations. Telescopes have the ability to make faraway objects appear much closer. As light passes through the objective lens it focuses, then as you look through the eyepiece it brings up the image from the focus point and magnifies it to the size of your eye’s pupil. Amazing tools like these helped the Corps of Discovery and many other geographers map out the United States.