39.Another duty of this department is the granting and recordingof patents.People are continually inventing a new machine or animprovement of an old machine.Not many years ago the farmers mowed their grass with a scythe，and all sewing was done by hand with a needle.But one ingenious man contrived a mowing machine，which is drawn by horses and cuts the grass very rapidly.And another equally ingenious inventor contrived a sewing machine，by which one woman can do in the same time as much work as several sewing in the old way.Such contrivances as these，and many others like them，are very useful.And to encourage men to plan them the government has made a law which allows an inventor the sole right to sell his inventions for a number of years.In this way sometimes great sums of money are made.The inventors of the telephone，the pneumatic bicycle tire，and the electric light，for instance，have become very rich.Such right to monopolize an invention is called a patent .Of course，as soon as the time of the patent has expired，any one can make or sell the article in question.The patent office grants patents to inventors，and keeps a careful record of such grants.
40.The United States owns many great areas of land.As we have seen，there was a time when nearly all the land west of the Alleghany Mountains belonged to the nation.But it has mostly been sold to private persons at a low price，or，indeed，actually given away.A dollar and a quarter an acre was the usual price for a long time.The desire was for the land to be settled and used，so that as many people as possible might have homes of their own and farms on which they might be earning a living for their families.About the time of the great civil war a law was made by congress permitting any head of a family to take 160acres of the public land for his own at a nominal cost，provided he would make it his home.A residence of five years on the land is required before the title is given，and no title is given at all except to a citizen of the United States.
41.Under the policy of sale at a low price，or，as at present，of actual gift，many thousands of families have found homes on the public land.The vast area west of the Alleghany Mountains was nearly all a wilderness a hundred years ago.Now it consists of many populous states，with great cities，churches，schools，libraries，and，what is moreimportant than all and indeed is the foundation of all，with multitudes of happy homes.
42.The public land is managed by the department of the interior.
43.The care of the Indian reservations is also intrusted to this department.This is a work requiring great intelligence and integrity.Bad management may result in Indian wars，and what people are doing to have the young Indians grow up good citizens will come to little if the government is not just and wise in its dealings.
44.The Department of Justice.The great amount of business done by the different departments makes it often necessary for the government to be concerned in a lawsuit.And it is also convenient that officers of the government should always be able to have the opinion of a good lawyer as to the exact meaning of some law in a particular case.So the president has as one of his cabinet an officer called the attorneygeneral.He is the government lawyer，and his department is the department of justice.
45.The Treasury Department.The department which takes care of the money of the government ranks next in importance after the department of state.But as it provides the means by which all the others do their work，it is put last here.The business of government is expensive.Officers and employees have to be paid salaries，material has to be bought and used，soldiers and sailors have to be fed and clothed.The entire cost of carrying on the federal government of the United States for one year is about 350，000，000.
46.This vast sum is paid to the government by the people，and is called the national taxes.A tax is money which the government takes from individuals for public purposes.
Congress makes laws which prescribe how the taxes shall be paid，and how great they shall be，and for what purposes they shall be spent.Neither the president nor any of his cabinet can spend a dollar of the public money unless permitted to do so by such a law.
47.By far the largest part of the national taxes is paid by people who bring goods from foreign countries.At every seaport or other place on the border is an office of the government called a customhouse.The customhouse officers inspect all goods brought from abroad and collectTHE TREASURY BUILDING，WASHINGTONThis is an imposing structure of sandstone and granite，occupying an entire square not far from the president‘s house.Unlike the latter，however，the treasury building is not set in the midst of beautiful and spacious grounds，but is surrounded by busy thoroughfares.It is said that President Andrew Jackson became impatient at the delay in choosing a site，so one day he walked out from the White House，and，planting his cane in the ground，exclaimed，“Build it here.”And there it was built.