1889.] MICE0SC0P1CAL JOURNAL. 187 



NOTES. 



In a Watch Factory. — Steel screws are made so minute that it 

 takes 180,000 of them to weigh a pound, and although simply steel, 

 they are worth many times their weight in gold. The naked eye will 

 scarcely recognize them as sci'ews at all ; but under a lense they assume 

 the perfect symmetry of little solid screws with rounded, slotted heads, 

 and good, sharp, shapely threads. The jewels, too, are cut from the 

 precious stones, generally garnets, and so small that one would hardly 

 find it if dropped. Yet each piece must be as definitely shaped as if it 

 weighed a pound. And not only so, but into the end of each a hole is 

 bored to receive a moving journal or trunnion. On the accuracy of 

 these largely depends the perfection of the watch, and here the thous- 

 andth of an inch variation from correct dimensions would be like Mer- 

 cutio's wound. It might just as well be "so deep as a well, nor so 

 wide as a church door," if it is to vary at all. 



Ferns. — Willard A. Stowell, 222 Second st., Trenton, N. J., has 

 in prepai'ation a catalogue of North American fei-ns, including Mexico, 

 Central America, and the West Indies. There are many catalogues of 

 ferns north of Mexico, but none include the whole continent of North 

 America. He will esteem it a great favor to receive any notes or com- 

 munications in regard to the ferns of Mexico and Central America, and 

 will be glad to exchange botanical specimens of the eastern United 

 States for ferns of the southwest. 



Thin Sections of Timber.— Mr. R. B. Hough, of Lowville, N. Y., 

 proposed at the Cleveland meeting of the A. A. A. S. a new method 

 of exhibiting and studying the structure of timber. He employs frames 

 made of card-board, holding three samples of the wood, each being 

 about 2 inches wide and 5 inches long, and from -g^-inch to g-^-inch 

 thick. These exhibit the wood in three relations ; one slice being 

 transverse across the grain, another radially running from the outside 

 towards the heart, and a third is a tangential section. The first and 

 second show both the sap-wood and the heart. They also reveal the 

 grain and the structure of the wood in a most beautiful manner. These 

 various frames are arranged in book form for the purpose of study and 

 examination. They retain all the characteristics of the wood, and are 

 easily recognized, while the effect of the light shining through them is 

 to show the peculiarities of the grain even more emphatically than 

 would be the case if one were looking at a mass of the wood. 



The Microscope in the Cronin Mystery. — In the early morning 

 of May 5th a trunk was found near Lake View, 111., with one end 

 thrust into a ditch. Captain Villiers and a detachment of officers 

 leaped into the patrol-wagon and made a furious run to the lonely spot 

 where the trunk stood. When they got there they found a large crowd 

 of gaping men and boys who had trampled the grass in every direction. 

 The trunk was taken to the station-house. The first thing Captain Vil- 

 liers did was to make a careful investigation of the trunk. He found 

 enough evidence to satisfy him that a grown person had been murdered, 

 thrust into the trunk, and then carted to the spot between the two cem- 

 eteries. 



The trunk had been locked after the body had been placed in it, and 



