NATURAL PHILOSOPHY. 131 



THE GONIOMETROSCOPE. 



MM. A. Huray and H. Leile, of Paris, have patented an instru- 

 ment denominated a goniometroscope, by the aid of which patterns of 

 flowers, lace, and other small objects, can be multiplied and reflected 

 at any given angle, from a triangle upward. The instrument consists 

 of wood, opening like a book. The two sides forming the case are 

 hinged at the back, so that when required they will stand on end, 

 theback being in a vertical position. The sides are each covered 

 on the inside with a thin sheet of copper plated with silver, and bur- 

 nished. These serve as reflectors, and the reflection is intended to 

 be made in the very centre of the pattern. A protractor a half- 

 circle marked off in degrees is secured at the top of one side of the 

 case, at a short distance from the hinged back. By this the different 

 angles can be readily found, the protractor being held firmly by a 

 small holder, having a regulating screw on the other side of the case. 

 Through each side of the case, near the opening part, there passes a 

 vertical needle, having a head upon it. A screw is cut upon this 

 needle, and it takes it into a thread in the hole of the case through 

 which it passes. This needle is a little longer than the case, and by 

 turning its head it can be made to enter the pattern and thus steady 

 the instrument. When the angle is to be changed, or the instrument 

 closed, the points of the needles are withdrawn into the case, by turn- 

 ing their heads. By placing a pattern or design to be copied for 

 sewed muslin work, or for printing so as to enlarge it, the pattern is 

 placed on the table between the leaves of this case, and it is reflected 

 from its polished reflectors upon a piece of prepared paper, set in 

 proper relative position to receive it above. It is a convenient in- 

 strument for those engaged in enlarging intricate designs for manufac- 

 turing purposes. 



NEW MODE OF LIGHTING THEATRES. 



A new mode of lighting theatres has been introduced into the Im- 

 perial Opera, at Paris, which appears to be a most excellent im- 

 provement. The gas burners of the stage are placed under the floor, 

 and the products of combustion are carried off by glass chimneys and 

 ventilating tubes extending to the roof. The luminous rays are col- 

 lected by a double reflector, and transmitted towards the stage by an 

 inclined opening. A piece of unpolished glass placed before this open- 

 ing modifies the glaring effect of the light reflected from the polished 

 surface of the reflector. The combustible dresses of the actresses can- 

 not come in contact with any of the gas jets thus arranged, and thus 

 one cause of accidents is removed ; while the heat and poisonous pro- 

 ducts of combustion are, at the same time, carried off by the arrange- 

 ment of the gas jets. 



COLOR OF WATER. 



"Water is usually considered to be colorless ; the blue or green color 

 noticed when it is in large masses being attributed to impurities. 

 From some experiments of Dr. Tyndall, which were recently exhib- 

 ited at the Royal Institution by Dr. Frankland, it has been proved 



