W. Mason — New Harmonic Analyzer. 



iSo 



are the coordinates of the derived area, refer to the same 

 axes. All machines of this type have a definite wave 

 length to analyze, which we will designate by the letter 



a^ then in terms of h and x, is 



'ZttX 



or a 



(3) 



Substituting this value of a in equation (2) , the expression 

 becomes 



2 7i7rX 



P^-2' 2 /* 27r 



Ky , (y/ - 2//) <^^^' = jj y ^'^^ 



dx, (4) 



Fig. 1. 



3f>-oi9 Hi- £ d^e . 



Differentiating this equation to get rid of the limits 



2 . 2 IITTX 



A 



K (y; - y/) dx' 



y sm — ^^ — dx. 



(5) 



The machine by which we propose to evaluate the 

 Fourier integrals consists of a framework, an arm, a 

 curve, and a straight edge. The framework is an L- 

 shaped piece of wood or metal, grooved on the bottom to 

 allow a zylonite curve to slip into place when the frame- 

 work is placed over it. Lugs placed in the framework 



Am. Jour. Sci. — Fifth Series, Vol. I, No. 6.— Juxe, 1921. 

 33 



