162 Prof. Magnus's Hydraulic Researches. 



described, plates could be introduced into the middle of the 

 bottom of this vessel, containing orifices of various diameters. 

 The streams issuing from these holes fell into a vessel placed 

 upon a soft support and quite separate from the above-mentioned 

 stand, in order that the motions in the receiving vessel might be 

 as little as possible communicated to the floor and thence to the 

 first vessel. Again, in order to reduce these motions to a mini- 

 mum, and to avoid the noise occasioned by the falling water, a 

 board was so placed in the I'eceiving vessel as to make a small 

 angle with the vertical, as is described in § 42. The jet of 

 water on falling upon this, slid down it so as to occasion a 

 scarcely audible noise. 



In order to make the stream as regular as possible, the " tran- 

 quillizer" {Bei-uhiger) described in § 38 was placed in the first 

 vessel. The circular motions in the water, and the consequent 

 twistings in the jet itself, were thereby avoided. 



Jets ivithout sivellings. 



118. In the first place, I must mention that repeated experi- 

 ments have convinced me of the correctness of the assertion made 

 in § 85, namely, that no sivellinffs whatever are produced in a 

 jet which flows out quite calmly, provided that the rotation of 

 the liquid in the interior of the vessel is prevented by the " tran- 

 quillizer," and that the jet is not subjected to the vibrations 

 produced by a note or otherwise. Such a stream forms a con- 

 tinuous, perfectly smooth mass, the diameter of which diminishes 

 with the distance from the efflux-orifice to the point where disin- 

 tegration commences. In its descent from this point the stream 

 assumes a turbid appearance ; at the same time it acquires a 

 greater diameter, presenting an appearance like that shown in 

 Plate I. fig. 1. There is no trace of alternate contractions and 

 expansions either in the smooth and continuous, or in the turbid 

 and discontinuous part. Now and then very small drops spirt 

 out laterally from the point of commencing turbidity, and often 

 also below it. This lateral projection of drops seldom occurs in 

 jets issuing from orifices of 5 millimetres and more in dia- 

 meter; but when the streams are narrower, the orifice being 

 about 1 millimetre in diameter, the whole water-current is disin- 

 tegrated into fine drops, thereby assuming the form of fig. 2. 



119. Savart* also mentions that the jet shows no swell- 

 ings when all vibrations in its neighbourhood are avoided. His 

 description agrees perfectly with that given in the previous para- 

 graph, with the exception that he does not mention the small 

 drops. In jets, however, of the diameter of those employed 



* Ann. de Chim. et de Phys. 2nd series, vol. liii. pp. 364, 366. 



