HA RD WICKE' S SCIENCE- G OS SIP. 



57 



These buds having once begun to grow adhere to the 

 woody layer at their base, and push out their point 

 through the bark towards the hght. The buds then un- 

 fold and develop leaves, which elaborate the sap carried 

 up the small shoot. Once elaborated, it descends by 

 the bark, when it reaches the base or inner bark. Here 

 it is arrested, so to speak, and deposited between the 

 outside and inner layer of bark, as can be observed 



for the future layer of woody matter, if the base 

 is not firmly connected, it is liable to be pushed out, 

 and lose its connection inwardly. Then the knot 

 may be said to be now entirely between the inner 

 and outer bark ; with a knot of woody matter ; or, 

 the woody layers and leaves. 



In those knots that retain their hold at the base 

 they are very liable to be enclosed in the future 



Fig. 31. 



Fig. 3^. 



Fig. 40. 



Fig. 32. 



Fig. 33- 



Fig. 37- 



Fig. 38. 



Fig. 39- 



Fig. 41. 



Fig. 42. 



Fig. 43 



on examining specimens on trees in the wood almost 

 anywhere. 



Then this growth, as we shall see, is due to a 

 defective circulation, because in these trees such as 

 the ash, sycamore, and oak, where the shoots are 

 more vigorous and strong, there are fewer knots 

 found, because the strong growth of the shoot causes 

 a better circulation. 



First, we note the bark of the silver fir, and the base 

 of the branch where it originally sprang from. Observe 

 this is of importance, for when the bark is expanding 



layers of woody matter, where they are found on 

 sawing up timber. The knot may be said to have 

 passed its first stage and is represented at Fig. 32, and, 

 as we have observed, is first due to the buds and 

 small shoots springing out of the bark. They are also 

 fed by the leaves which they develop, as they 

 generally lose their leaves about the second and 

 third year. The shoots also dying back (see Figs. 33, 

 34, 35. 36, 37, 38, 39, 40). Then how do they grow 

 and attain a large growth, seeing that they are deprived 

 both inwardly and outwardly of any visible means of 



