PROCEEDINGS, OCTOBER. Ivii 



of highly interesting specimens shown at work under microscopes of 

 diflferent power. 



The Chairman asked, as they never slept and never rested, whether 

 Mr. Bastow knew how long thej lived ? 



Mr. Bastow said he had had them under a microscope for a month, 

 but he did not know how long they lived. 



Mr. R. M. Johnston said he had seen two species of rotifer near St. 

 Xeonards with Mr. Harrap, of Launceston, who with one or two friends 

 had made a valuable collection, and used formerly to write some inter- 

 esting papers for the Society. He would like to communicate Mr. 

 Bastow's observations to Mr. Harrap, and the secretary might ask that 

 gentleman to again favour the Society with the result of some of his 

 researches. 



"alpha centauri." by a. B. Biggs. 



A paper on the double star Alpha Centauri, accompanied with a 

 diagram showing a projection of its real orbit from its apparent curve 

 was, in the absence of the author, read by the secretary (Mr. A. 

 Morton.) The paper drew attention to the special interest attaching to 

 this star, from its being, so far as known, the nearest fixed star to the 

 solar system (225,000 times the earth's distance from the sun) ; that it 

 is one of the finest object? of its class in the whole heavens ; and, that 

 being invisible to the observatories of the Northern Hemisphere, science 

 is indebted to southern observers for all that can be known of it. A 

 clear description was given of the method employed in the investigation, 

 which included an enormous number of observations extending from. 

 1818 to the present time, of which the author's measures extended from 

 1882. 



The most interesting deductions from the investigation are as 

 follows : — 



The maximum apparent angular distance separating the pair is 23jsecs, 

 of arc, which occurred in 1818, the next occurrence being in 1902. The 

 actual mean distance of the comparison from its primary is a little over 

 20 times that of the earth from the sun. Its period of revolution is 84f 

 years, both period and distance corresponding very closely with those 

 of the solar planet Uranus. The nearest apparent approach of the stars 

 to each other was in 1885, namely, 1 7-lOth sec. of arc, they being 

 then so close that high telescopic power was necessary to divide them 

 at all. The actual orbit is inclined (or tilted) from the line of sight 

 79deg., hence its apparent curve is a very long, narrow ellipse. 



From the actual mean distance of the companion from its primary, 

 and its period of revolution, the author computes the mass of the 

 principal star to be about 1 l-7th times that of the sun. 



The author's observations of the star were given in a table, and also 

 an ephemeris showing positions and distances for subsequent years up 

 to 1901. 



THE ECHIDNA. 



Mr. A. Morton submitted a paper entitled "On the egg of the echidna, 

 or porcupine." He stated that till the year 1888 very great doubt existed 

 in the minds, not only of naturalists but of all observers as to how the 

 •echidna brought forth its young, when Mr. Caldwell, a student of 

 •Cambridge, who took the Balfour Travelling Scholarship, left to travel 

 in the Australian colonies to study the embryology of the marsupial, the 

 monotremata, and the ceratodus. Mr. Caldwell, with most other 

 scientists, states that he was under the impression that the echidna and 

 platypus were born in the same way as the marsupials ; but in Queens- 

 land, assisted by the blacks, he was enabled to procure many specimens 

 which set at rest the question, and enabled him to decide that they 

 were oviviparous. This important discovery was made known to 



