VOL. XLIV.] PHILOSOPHICAL TRANSACTIONS. 235 



we may plainly perceive a sort of capillary tubes. Here we may be at a loss for 

 a passage for the acting matter of the farina; we must therefore look further. 

 On cutting these threads longitudinally, they appear in many places as this before 

 us, and are often pretty full. The occasion of these appearances, fig. 3, he 

 owns he is not botanist enough to solve, nor will the first magnifier give him 

 satisfaction. At the bottom of these, set round the stem, is a single row of 

 small threads, not exceeding half an inch : these appear to have much broader 

 heads than the long purple threads around them ; and being so well secured and 

 fortified from injury, may be of great use and consequence to the flower; yet 

 they appear set in the same manner, though the tubes do not rise so high. 



On the top of the flower are 3 stamina placed on the uterus: these are set in 

 a manner described before with tubes, but, on making a longitudinal section, he 

 could not find them carried on in any shape. In the uterus he could not observe 

 any tubes at all ; nor any appearance remarkable, till coming to the bottom of 

 the stylus; and then, by degrees, from a smaller to a greater it rises, till the 

 appearance becomes as represented in fig. 4. 



On examination, he found the 5 appearances to answer the 5 stamina, on which 

 the apices are set; and from this appearance, growing nearer and nearer to each 

 other by degrees, they join at last all in one in the stalk of the flower. 



Concerning an Improvement of the Weather-Cord. By Mr. JVm Arderon, 



F. R. S. N" 479, P- 169. 



The weather-cord is an hygrometer of a very ancient invention; and, if pro- 

 perly constructed, may be made use of with very good success, to show the va- 

 rious alterations of the atmosphere, in respect to moisture and dryness; but, as 

 commonly made, it never rises or falls sufficiently to point out such minute 

 changes as the curious would be desirous to know. A sense of this defect set 

 him on endeavouring to find out some method of removing it, as follows : 



In fig. 5, pi. 5, he only fixed the end of the index ab fast to the silk ce at a, 

 leaving it lying loose on the point d ; and in this manner the other end of the 

 index would nearly describe the arch pgh ; but then he soon perceived, that the 

 centre of motion, on which the index turned, was changed whenever it moved 

 ever so little; and consequently that the arch struck by the end b must be 

 irregular. 



On considering this, he toothed 2 pieces of brass, as 1,2, and 3, 4, fig. 6, to 

 fit each other so exactly, that on the least motion of the one, the other would 

 move; then fixing the index on the centre c, its motions were rendered much 

 more regular. He placed also a little collar of brass at b, on the cord sr, and 

 to that collar tied the silk, which gave motion to the index, that the cord sr 

 might twist and untwist without any impediment. 



H h 2 



