43 



POPULAR SCIENCE MONTHLY. 



The Ball Xozzle. Mr. Arthur Kitson, in 

 an address on the ball nozzle, published in 

 the Journal of the Franklin Institute, gives 

 the following explanation of its apparent 

 contradiction of natural laws : The problem 

 connected with this invention may be put 

 thus: Why does the ball adhere to the 

 nozzle when there is behind it a force ag- 

 gregating as high as hundreds of pounds 

 pressure ? The explanation usually given is 

 that the atmospheric pressure holds the ball 

 in its place and prevents it from falling or 

 leaving the mouth of the nozzle. To this 

 others answer that the pressure behind the 

 ball far exceeds the atmospheric pressure ; 

 for instance, there is an exhibition given 

 daily in New York with one of these nozzles 

 where the water pressure equals a hundred 

 pounds per square inch, and as the atmos- 

 pheric pressure is only about fifteen pounds, 

 it would at first sight seem that the excess of 

 pressure on the under side of the ball was 

 eighty-five pounds, and ought, therefore, to 

 expel the ball. The error, however, in this 

 argument arises from failure to distinguish 

 between the pressure of the water when con- 

 fined in the pipes and when issuing around 

 the ball. It is very certain that if a hundred 

 pounds pressure were acting directly upon 

 the ball, it would be blown out of the nozzle, 

 but it does not appear to me to act in this 

 way. When the ball is confined to the 

 mouth of the nozzle and pressed against it, 

 it is undoubtedly subjected to the pressure 

 of the water, but the moment it is raised 

 slightly from the mouth, it is no longer sub- 

 jected to this pressure, since the water is 

 escaping all around it. In this respect it 

 resembles the lid of a teakettle when the 

 water is boiling. By plugging the spout, the 

 lid will be raised by the steam pressure suf- 

 ficiently to allow the steam to escape at the 

 sides. The explanation that seems to me to 

 be the correct one is as follows : The ball is 

 acted upon by three forces : first, gravity ; 

 second, atmospheric pressure ; and, third, the 

 force of the issuing stream. At first, the at- 

 mospheric pressure is the same at all points, 

 and hence gravity has free play ; but as soon 

 as the stream passes through the nozzle, the 

 atmospheric pressure from the under side is 

 counteracted by the momentum of the issu- 

 ing water, and the ball rising to a point 

 where the water can pass freely around the 



sides, without pressing materially upon the 

 ball, we have the full pressure of the atmos- 

 phere on the under half-side of the ball re- 

 sisting the force of gravity. The ball, there- 

 fore, simply serves as a deflector to divert 

 the current of water or to spread it out, and 

 the resistance of the atmosphere against the 

 ball suffices not only to perform this opera- 

 tion but also to sustain its weight. 



It is possible that the density of the air 

 may also be somewhat increased under the 

 ball by the action of the spray. With a 

 heavy pressure, the ball is farther removed 

 from the nozzle than with a light pressure. 

 The same holds good respecting a heavy ball 

 and a light ball. 



Native Snlphnr in Michigan. Beds of 



native sulphur are described by W. H. Scher- 

 zar in the American Journal of Science as 

 having been discovered during the past year 

 in the upper Ilelderberg limestone of Mon- 

 roe County, Mich. They lie from sixteen to 

 eighteen feet below the surface, between a 

 compact, dolomitic limestone and a calcare- 

 ous sand rock. They consist of a yellowish- 

 brown, impure limestone, containing fossils, 

 and giving here and there a strong, oily odor, 

 which, wherever exposed to view, appears to 

 be cavernous in structure, having pockets of 

 from a fraction of an inch up to three feet in 

 size. These pockets contain scalenohedrons 

 of calcite or tabular crystals of celestite, or 

 both together; while the sulphur generally 

 occurs in bright, lustrous masses toward the 

 center of the cavity, intermatted frequently 

 with the lime minerals. Fragments as large 

 as one's fist are readily removed. Some of 

 the smaller cavities contain nothing but pure 

 sulphur. Nearly one hundred barrels of pure 

 sulphur have been obtained from about an 

 acre of this bed. 



Antlrabie Senna. In the light of some 

 of the recent experimental work of Tizzoni 

 and Centanni, published in the Lancet, there 

 seems little doubt that a great advance has 

 been made in the treatment of rabies. In- 

 stead of manufacturing the antitoxic mate- 

 rial in the body of the patient, by a process 

 of vaccination as in the Pasteur method, 

 Tizzoni and Centanni prepare this substance 

 in an animal, from which it is conveyed to 

 the individual to be treated, in the blood 



