MISCELLANY 



7^S 



trees were of the female kind. He specifies 

 that the larch, while in its highest luxuri- 

 ance, and during many years, produces only 

 female flowers ; but in its decline it at 

 length produces male flowers, and it short- 

 ly afterward dies. Prof. Hartshorne ex- 

 tended this theory to animal life, and un- 

 dertook to show that, whenever or wher- 

 ever there was excess of formative power, 

 its tendency was to the production of fe- 

 male offspring. He illustrated his belief by 

 the development of bees, the birth of the 

 queen-bee being the highest, of the drone 

 the lowest result, and preceded by respec- 

 tively high and low circumstances of nutri- 

 tion. Sometimes a working-bee which, 

 being an imperfect female, is of course in- 

 capable of impregnation will give birth to 

 parthenogenetic offspring. Such offspring 

 is always male. The eggs of the queen-bee 

 that hatch males have not been fertilized ; 

 and, should she never have been impreg- 

 nated and lay eggs, they will hatch only 

 drones. In respect to the aphides (plant- 

 lice), it is noticeable that, while their food 

 is sufficient and of nutritious quality, their 

 offspring is exclusively females, propagated 

 parthenogenetically ; but soon after the 

 supply of food, owing to a change of sea- 

 son or circumstances, is diminished, young 

 male aphides appear. Among the higher 

 order of animals Prof. Hartshorne found an 

 argument in the sex of double monsters. 

 Stating that the birth of double monsters 

 was due to fissure of the ovum and excess 

 of formative power, he asserted that it is 

 well known that in the majority of instances 

 these monsters were of the female sex. He 

 brought forward the vital statistics of dif- 

 ferent nations and their varying proportion 

 of male and female births in support of 

 his position, attributing the differences to 

 increasing or diminishing vitality; and even 

 the continually lessening reproductive pow- 

 ers of American women formed one of the 

 illustrations of this theory. 



SYMPATHETIC VIBRATIONS. 



Prof. Joseph Lovering, of Cambridge, 

 Mass., gave an interesting address on vibra- 

 tion, illustrated by an experiment. It was 

 presumed that the members were more or 

 less familiar with Milde's experiment with a 

 tuning-fork and vibrating thread. This op- 



tical method of Milde is very much im- 

 proved by using a large bar of iron and 

 perpetuating the motion by means of mag- 

 netic excitement, the vibration being thus 

 maintained for any length of time. A cord 

 20 or 30 feet in length is thus thrown into 

 vibration. When the first suspension 

 bridge was building in England, a fiddler 

 offered to fiddle it away. Striking one note 

 after another, he eventually hit its vibrat- 

 ing note, or fundamental tone, and threw 

 it into such extraordinary vibrations that 

 the bridge-builders had to beg him to de- 

 sist. Only recently a bridge went down 

 under the tread of infantry in France who 

 had not broken step, and 300 were drowned. 

 An experiment is often referred to of a 

 tumbler or a small glass vessel being broken 

 by the frequent repetition of some particu- 

 lar note by the human voice. It is said, and 

 may be true, that certain German tavern- 

 keepers increase their custom by the occa- 

 sional performance of this feat. In the 

 Talmud there is a curious question raised 

 as to what would be the damages if a do- 

 mestic vessel were broken by a noise made 

 by an animal, such as a barking dog. Prof. 

 Lovering here exhibited two pieces of 

 clock-work, each giving a button a circular 

 velocity of rotation. These are to turn a 

 cord much as a skipping-rope is turned. 

 The rotation twists an ordinary cord or 

 untwists it, as the case may be and to 

 avoid this twisting a tape is substituted, 

 and a twisting or rotating machine is placed 

 at each end. The chief difficulty now re- 

 maining is to have the machines twist in 

 unison, which is difficult, as the two pieces 

 of clock-work vary from each other, but 

 on the whole the experiment is usually sat- 

 isfactory. The tape was stretched across 

 the stage, and the machines to rotate it 

 were placed at each end. If the string is 

 too slack for one segment of vibration, it 

 subsides into parts, each having a vibration 

 similar to the other. The tighter the string 

 is drawn, the fewer the segments of har- 

 monic vibration. The string started with 

 five waves or segments of vibration. Drawn 

 tighter, these were reduced to four, three, 

 and finally two segments, the nodal point in 

 each instance between the waves remaining 

 perfectly unmoved. With a shorter string 

 the first harmonic note was reached, and 



