1858. 



NEW ENGLAND FARMER. 



33 



such a degree about the furnace, as to set on fire 

 the wood-work. The self-acting regulator I think, 

 ■will be understood by referring to the accompa- 

 nying diagrams. 



Fig. 1 is a vertical section through the regula- 

 tor and supply pipe, showing the valve in its po- 

 sition when not afifected by currents ; the dotted 

 lines representing its position when the inner 

 wing, b, is closed by a refluent current, the weight, 

 €, still hanging plumb. When the tendency to 

 vacuum about the mouth of the pipe ceases, the 

 current turns inward and the inner wing instant- 

 ly opens. 



Fig. 2 is a similar section, showing the posi- 

 tion when the outer or perforated wing, a, is clos- 



ed by the force of the inward current, the weight, 

 e, preventing it from closing too freely, and 

 tending to throw it up when the pressure dimin- 

 ishes. 



Fig. 3 is a plan with the cover of the supply 

 pipe removed. 



The equipoise, c, can be adjusted by the joint, 

 d, so that either wing can be made to propon- 

 derate ; or so that if the weight, e, is removed 

 and all currents, the regulator will be balanced, 

 and remain in any position it may be placed in 

 its bearings. 



Mine has been operating a few weeks only, but 

 sufficient to show that it is a very efficient and 

 useful sentinel. There being a good fire in the 



furnace, and the thermometer indicating about 

 32 degrees outside, the tendency to equilibrium 

 produced a cui-rent through the supply pipe of 

 about five miles per hour, (about seven feet per 

 second,) and sufficient to close the outer wing of 

 the regulator, as I had the weight, e, adjusted. 

 In colder weather it would be much more, as the 

 contrast between the external and internal air 

 would be greater. In a mild day, when the tem- 

 perature inside and out is nearly equal, there is 

 hardly any perceptible current. 



The regulator may be applied to chimneys, es- 

 pecially where coal is used, to prevent smoke and 

 gas from blowing down, and to produce a uni- 

 form draught. 



Very respectfully yours, 



Henry B. Osgood. 



Whitinsville, Worcester Co., Nov. 23, 1857. 



i^° A gentleman in Rockingham county, Va., 

 has lost five head of young cattle, and two fine 

 milch cows, within five days, by permitting them 

 to run in the same field where he was feeding his 

 hogs. The hogs ate the stalks of corn, and left 

 them on the ground after chewing. These were 

 taken up by the cattle, eaten, swallowed, and not 

 being digestible, produced an itching all over. 



They at once commenced rubbing their heads, 

 when their throats swelled, and in a short time, 

 death ensued. So says a Virginia paper. 



THE CUNIflNG OF THE BAVEN. 



In the narrative of the Arctic Voyage of Capt. 

 McClure, of the British Navv, is the following 

 story of the two ravens, which became domici- 

 lated on board the Investigator. The raven, it 

 appears, is the only bird that willingly braves a 

 Polar winter, and in the depth of the season he 

 is seen to flit through the cold and sunless atmo- 

 sphere like an evil spirit, his sullen croak alone 

 breaking the silence of the death-like scene. No 

 one of the crew attempted to shoot the ravens, 

 and they consequently became very bold, as will 

 be seen from the following story : 



"Two ravens now established themselves as 

 friends of the family in Mercer Bay, living main- 

 ly by what little scraps the men might have 

 thrown away after meal times. The ship's dog, 

 however, looked upon these as his especial per- 

 quisites, and exhibited considerable energy in 

 maintaining his rights against the ravens, who 

 nevertheless outwitted him in a way which amus- 

 ed every one. Observing that he appeared quite 

 willing to make a mouthful of their own sable 



