132 



THE GUIDE TO NATURE. 



they will eat only about three times 

 through the season, but if they eat 

 only a little, such as a single mouse, 

 they will eat again in about two 

 weeks. 



The young rattlesnakes are provided 

 with teeth and poison fangs when 

 born, and the two poison glands in 

 the upper jaw contain the venom 

 ready for immediate use. 



Snakes take water frequently and 

 after eating are very sluggish until 

 their food is digested. They also take 

 regular baths. 



A rattlesnake can spring to a dis- 

 tance equalling, at the most, from 

 about one-half to two-thirds of its 

 length, and will generally strike below 

 the knee if a person is standing. It 

 is not necessary for a rattlesnake to 

 coil before it bites because its two 

 poison fangs are very sharp and all 

 it has to do is to bend its neck into 

 an S-shape and hook on, when the 

 fangs quickly penetrate the flesh. 



Snakes' tongues, wrongly called 

 stingers, are harmless. They are 

 used to feel the way while the snake 

 is blind, which is for only a few days 

 while shedding the skin, an event that 

 occurs three times a year. 



When I am handling a live rattle- 

 snake I can feel a buzzing vibration 

 all through the snake's body when it 

 is rattling, and I have a similar feel- 

 ing in my fingers and hands. The 

 sensation is like that caused by a 

 slight shock from an electric battery. 



How snakes crawl is to most per- 

 sons a mystery. In order to see the 

 movement, we should have to see a 

 living skeleton, and if we could do 

 that we should see all of its ribs in 

 motion. The ribs are the snake's legs 

 while the belly scales are its feet, 

 therefore the movement is internal 

 and cannot be seen. 



Rattlesnakes are among the most 

 deadly of reptiles and should be 

 feared by all. 



P6PULWU\STRdN5MY 



The Heavens in July. 



BY PROF. S. ALFRED MITCHELL, OF 

 COLUMBIA UNIVERSITY. 



The most interesting astronomical 

 object for the year 1909 is unquestion- 

 ably the planet Mars, which comes 

 closer to the earth than it has since 

 the year 1892. Much will be written in 

 newspapers and magazines concerning 

 the ruddy planet, and it would be well 

 to know how much to believe of what 

 is written, or how big a grain of salt 

 to take. Already we hear talk of sig- 

 nalling to Mars by mirror and by wire- 

 less. Mars, like the earth, is a planet 

 and circles the sun in its orbit. The 

 earth goes about the sun almost in a 

 circle with the sun only a million and 

 a half miles from its center. As every- 

 body knows, the distance from the 

 earth to the sun is nearly 93,000,000 

 miles. The average distance to Mars 



is 1-52 times greater than this, or 141,- 

 500,000 miles, but its orbit does not so 

 closely approximate a circle, for the 

 sun is 13,000,000 miles away form the 

 centre, so that the greatest distance from 

 sun to Mars is 154,500,000 miles, the 

 least distance 128,500,000 miles. It 

 needs only an elementary knowlege of 

 astronomy to enable anyone to draw 

 the approximate paths of earth and 

 Mars about the sun, and the whole 

 orbits may readily be plotted out by 

 the aid of a ruler and pair of com- 

 passes. Draw a circle with a radius of 

 2.33 inches. The center S of this circle 

 will represent the sun, and the circle 

 the path of the earth. Draw any di- 

 ameter of the circle. Lay off a dis- 

 tance, S M, equal to 0.33 inches, with 

 M as centre draw a circle with radius 

 of 3.53 inches. This second circle will 

 closely represent the orbit of Mars. 



