526 



HENDERSON'S HANDBOOK OF PLANTS. 



Measuring Trees, Etc. This very simple plan 

 of ascertaining the height of trees, etc., is 

 taken from the Journal of Horticulture (London, 

 July, 1888). The tree measurer on the right 

 of the figure consists of a staff six feet long, 

 pointed for pressing into the ground. To the 

 centre of the staff a piece of half-inch board 

 twelve inches wide and exactly square is 

 affixed with screws. The diagonal cross 

 lath is three feet long and perfectly straight. 

 It may be fixed or movable ; if the latter, 

 a small button being screwed on the board 

 for it to rest on when in use . The plumb 

 line is indispensable, as no correct measure- 



ment can be had without it. The plumb- 

 bob may be about the size of a small walnut, 

 the string passing through its centre. 



In measuring the tree, the staff is placed 

 at a distance from it, so that with the 

 plumb exactly perpendicular the cross lath 

 points to the top of the tree. The person 

 taking the "sight" resting on one knee 

 or reclining to bring the eye to the bottom 

 of the lath. The lath is then drawn to the 

 ground, where the end rests at C in the 

 figure, or, if the lath is fixed, a string will 

 answer the purpose of extending the sight- 

 line to the ground. From this point G to 

 the centre of the trunk will represent the 

 actual height of the tree ; or to put the matter 

 concisely, the horizontal line A C is equal to 

 the vertical A B. 



When the ground is irregular, provision 

 must be made for having the line level from 

 the root of the tree, or A in the figure, to C. 

 The central board must be a true square, 

 the perfectly straight sighting lath resting 

 across it exactly from corner to corner, as 

 the least deviation will lead to error, and the 

 weight must hang positively plumb, other- 

 wise the measurement will not be accurate. 



Measuring the Width of a River. The ap- 

 proximate breadth of a river or other stream 

 may be determined by means of the brim of 

 a hat or the peak of a cap, and this can be 

 done by a boy as well as a man. The person 

 desiring to ascertain this fact must place 

 himself at the edge of one bank of the river 

 and lower the brim of his hat, or peak of his 

 cap, till he finds the edge just cuts the other 

 bank ; then, after placing the hand under the 

 chin, so as to steady his head and keep it in 

 exactly the same position, he must turn round 

 steadily till he faces some level ground on his 



own side of the river, and observe when the 

 edge of the peak again meets the ground. 

 The measure of this distance will be very 

 nearly the breadth of the river. 



Common and Chemical Names of Various 

 Substances. Aqua fortis is nitric acid. Aqua 

 regia is nitro-muriatic acid. Blue vitriol is sul- 

 phate of copper. ' Cream of tartar is bitartrate 

 potassium. Calomel is chloride of mercury. 

 Chalk is carbonate of calcium. Salt of tartar is 

 carbonate of potassa. Caustic potassa is hy- 

 drate potassium. Chloroform is chloride of 

 formyle. Common salt is chloride of sodium. 

 Copperas, or green vitriol, is sulphate of iron. 

 Corrosive sublimate is bichloride of mercury. 

 Dry alum is sulphate aluminum and potassium. 

 Epsom salts is sulphate of magnesia. Ethiops 

 mineral is black sulphate of mercury. Fire damp 

 is light carburetted hydrogen. Galena is sul- 

 phide of lead. Glauber salt is sulphate of so- 

 dium. Glucose is grape sugar. Goulard water 

 is basic acetate of lead. Iron pyrites is bisul- 

 phide of iron. Jeweler's putty is oxide of tin. 

 King's yellow is sulphide of arsenic. Laughing 

 gas is protoxide of nitrogen. Lirne is oxide of 

 calcium. Lunar caustic is nitrate of silver. 

 Mosaic gold is bisulphide of tin. Muriate of 

 lime is chloride of calcium. Nitrate of salt- 

 petre is nitrate of potash. Oil of vitriol is sul- 

 phuric acid. Potash is oxide of potassium. 

 Kealgar is red sulphuret of arsenic. Red lead 

 is oxide of lead. Bust of iron is oxide of iron. 

 Sal ammoniac is muriate of ammonia. Slacked 

 lime is hydrate calcium. Soda is oxide of so- 

 dium. Spirits of hartshorn is ammonia. Spirits 

 of salt is hydrochloride of muriatic acid. Stucco, 

 or plaster of Paris, is sulphate of lime. Sugar 

 of lead is acetate of lead. Verdigris is basic 

 acetate of copper. Vermilion is sulphide of 

 mercury. Vinegar is acetic acid diluted. Vol- 

 atile alkali is ammonia. Water is oxide of 

 hydrogen. White precipitate is ammoniated 

 mercury. White vitriol is sulphate of zinc. 

 Iron. 



Quantity and Weight of Water in Six Feet 

 of Pipe of the Following Diameters : 



For double the diameter multiply contents lour times. 



Weight of Lead Pipes per Foot : 



Strength of Rope. A good rope will sustain a 

 weight in pounds equal to the number of the 

 square of the circumference in inches, multi- 

 plied by 200. Thus, a rope three inches in 

 circumference, or one inch in thickness, will 

 sustain 1,800 pounds with safety. 3x3=9X 

 200=1, 800 Ibs. 



