26 JOURNAL OF SCIENCE, 
VIIL.—Nores on Woot.—By G. W. Tirren AND E. WHITECOMB, 
Spirally growing hair is termed wool. 
It much resembles ordinary hair in its habit of growth, and possesses 
numerous imbricating scale-like protruberances on its surface. These, when 
viewed under the microscope, present the appearance of serrations at its margin, 
and of a network on the surface. 
These serrations are very important, as it is chiefly due to them that wool is 
capable of being felted ; those wools possessing serrations of greater height, and 
a greater number of serrations to a given length, being more valuable for this 
purpose than others. 
But this is not the only point which affects the value, for its fineness, wave, 
and length of staple, are of importance. The object, therefore, of wool growers 
is to produce the finest wool of good staple, which at the same time contains the 
maximum number of serrations per inch, and which has also the greatest 
waviness. 
Taking these things into consideration, together with the fact that such fine 
work cannot be done witb the naked eye, we have started a series of examina- 
tions of wools under the microscope. The results of our investigations are 
contained in the following lines :— 
In examining wool under the microscope it is necessary to observe the 
following points, more especially if it is intended to make drawings of the wool 
examined, in order to find their relative thickness. 
1.—The same microscope fitted with the same power must be used for every 
examination. 
2.—The camera lucida must always be at the same angle and distance from 
the paper. 
We next come to the mounting— 
First of all it was necessary to find out what part of the wool to mount in 
order to get a good average thickness, as the wool has not the same thickness 
threughout. Youatt states that the wool produced in winter is thinner than 
that produced in summer, which may be accounted for by assuming that, as is 
generally the case, the sheep during that season had not sufficient food, which by 
affecting them would also affect the wool, causing it to become thin. 
Youatt states that the tip of the wool is thicker than the rest. This may 
also be accounted for in somewhat the same way, if we assume that after shearing 
the food was more plentiful than usual. It may also be accounted for by as- 
suming that the sheep being cold after shearing, nature exerted herself by 
increasing the rapidity of the wool growth in order to cover the sheep quickly. 
After repeated examinations of different parts, namely, near the base, middle, 
and tip, we came to the conclusion that near the middle would give the best 
results, not only on account of its giving a fair average thickness of the whole 
staple, but also because portions taken from near the tip showed fewer and less- 
distinct serrations, probably through their having become worn off by the con- 
stant friction of the wool. 
We tried mounting in Canada balsam, chloroform, and in carbol-glycerine. 
The glycerine gave the best results, as the serrations were more pronounced ; 
the reason being that the refractive power of the Canada balsam is more like 
that of the wool than that of the glycerine. Canada balsam not mixing with 
water or alcohol, wool cannot be mounted direct from either of these, or it will 
be hidden by a cloud of opaque Canada balsam. Oil of cloves or chloroform will 
mix with Canada balsam, but not with water. Therefore, the water has to be 
got rid of by washing in alcohol, and then the alcohol by washing in oil of cloves 
or chloroform, then from this the wool can be putjin Canada balsam. Glycerine 
mixing freely with water, the wool can be mounted in glycerine direct, after 
having been washed in water. For washing, alcohol, potash solution, or other 
substances can be used, 
We found alcohol the best, as potash is very liable to dissolve the serrations 
if used hot or at all too strong. We also tried to form a deposit of gold or silver 
in serrations, so that they might show more clearly. The solutions used were 
Ag. NO3, 1 per cent. solution, and also Au. Cl3, 1 per cent. solution. We 
obtained the best results from the silver, leaving the wool in it about 15 seconds, 
and then washing. With the gold the results are not, as yet, satisfactory. 
In taking samples for examination they should be taken from the same part 
or parts of the sheep, as it will be found that at different parts of the animal the 
quality varies; that from the shoulder differing widely from that found on the 
belly. In a few cases great irregularities were found in the thickness of a single 
fibre, 
