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There are two inconveniences connected with this method, which are, however, more apparent than real. The first is, that as one shutter opening ends on the same horizontal line as that at which the other begins, there is a part of the sky not reached by the telescope; this is met by having a subsidiary shutter underneath the horizontal one. This shutter is of the same width as the opening, and about 2 feet in depth; it opens on hinges, and hangs down close to the inside, but as it is found to be rather in the way sometimes, it is proposed to put it on hinges that will allow of its being opened back outside.
The second inconvenience is, that sometimes the dome has to be rotated through the angle which separates the openings, if an object while being observed for a length of time happens so to vary in altitude that the change has to be made from one opening to the other.
In practice, I may say that the latter of these difficulties seldom occurs, and the former entails so little extra trouble in working, or expense in construction, that it is not a matter of practical inconvenience, while--and I now speak after a year's constant use—the framework continues quite unaltered in shape, and none of the shutters have at any time exhibited any signs of flexure.
I believe that this mode of construction is a novel one, and I think it will prove even more useful in much larger observatories than in one of this size.
The base of the dome is made of three rings of pine, each 9 inches wide and 1 inch thick, well screwed together, and to its lower side is attached a rack-wheel, which is 13 feet 3 inches in diameter and 5 inches in width, made in fourteen segments. The rail which runs on the twelve grooved wheels that are fixed to the wall below, is in the outside of this wheel and in the same casting. By making the rack-wheel and rail in the same casting the stiffness of the dome is increased, and a perfectly circular rail is secured, which makes its rotation very easy ; it is turned by a pinion gearing into the rack-work, to which is fixed a wheel of about 18 inches diameter.
The study of Observational Astronomy differs from almost all other scientific pursuits, in that it is entirely dependent upon the state of the weather; and as in this part of the world the weather is much oftener unfavourable than favourable, it is requisite that the short available time should be economised to the utmost. Now, there is no better way of accomplishing this than by having everything connected with the telescope and the observatory arranged so that the least possible time is consumed in starting work. It is also well that all moving parts shall act smoothly and without the use of a great degree of force for it is impossible after any considerable muscular exertion to turn round and make a fine micrometrical observation.
In all the details which I have described, and they are only those in which any novelty of construction occurs, these points have been carefully considered.
The telescope for which this observatory was designed is an equatorial reflector, made by Mr. John Browning; the diameter of the silvered glass speculum is 94 inches, and the focus 6 feet 6 inches. Its performance is excellent, both for space-penetrating power and for the manner in which it divides the closest double stars.
Mr. G. H. MORTON, F.G.S., read a communication on “ The Borings for Water at Bootle.” As these Borings are not yet completed, the printing of the communication is deferred for fuller information.
Ladies were present at this Meeting.
TWELFTH ORDINARY MEETING.
JOHN J. DRYSDALE, M.D., PRESIDENT, in the Chair.
Dr. NEVINS stated that he had received a letter from his son, Mr. Arthur Nevins, one of the Associate Members of the Society, giving the results of further experiments for testing Mr. Hartnup's laws for the Correction of Marine Chronometers, described by him in vol. xxx. of the Proceedings of this Society.
The ship “British Sceptre ” was recently sailing from Australia to Madras, and, having horses on board, desired to water at the Keeling Islands, lying about mid-way between these two places. These Islands are a circle of detached Coral Islands, of which the broadest is scarcely a mile across, the diameter of the circle being about as large as from Liverpool to Aintree,* while the highest land in the whole group is barely the height of the Exchange buildings. After being eighteen days at sea, they believed themselves to be nearing this group, and compared the three chronometers which were in the ship. When the rate of error given with each chronometer was applied in the ordinary manner, the ship appeared to be as far from the situation of the principal Island as from Egremont to the Town Hallt by one chronometer; as far as from Formby to the Town Hall: by the second; and about twice the distance of Southport from the Town Hall 9 by the third. When, however, they were corrected by the application of Mr. Hartnup's law, they agreed so nearly that the captain sent an officer aloft to look out, and he had not been there above five minutes before a point of land appeared in the horizon.
* About five miles.
About eleven miles.
+ Under two miles.
These Islands were first colonised some forty or fifty years since by an old navy captain, named Ross, who married a Malay woman, and induced other Malays to settle there. They now belong to his five sons, who have all been to England, and received a University education in Edinburgh, and the eldest is also a skilled engineer. They manufacture cocoa-nut oil to the value of £10,000 a year, which they send for sale to Batavia, and they are now building a new vessel in the Island for carrying on their trade. The Islands have become an important station of late, in consequence of the advantages they possess for supplying fresh water to ships sailing from Australia to the East Indies, as they lie in the fair way of the passage.
Mr. STEARN described some further experiments he had made with the telephone, with regard to the effect of the vibrations on the plate, at the receiving end of the wires.
Mr. E. R. RUSSELL then read a Paper on “ Trevelyan's Macaulay."*
Ladies were invited to this Meeting.
THIRTEENTH ORDINARY MEETING.
ROYAL INSTITUTION, April 15th, 1878. JOHN J. DRYSDALE, M.D., PRESIDENT, in the Chair.
The PRESIDENT brought in a communication from the Council, recommending the adoption of the following Memorial against the grant of a University Charter to Owens College, Manchester :
“ Your memorialists have considered the memorial recently presented to your lordships by the Owens College, Manchester, praying that a charter be granted to it conferring upon it the rank of a university, to be called the University of Manchester, and having the power to grant its own degrees in the faculties of Art, Science, Medicine, and Law.
* See page 257.
“Your memorialists are of opinion that the incorporation of a new university is undesirable ; but that, if such an institution be established, its constitution should be such as to enable it to incorporate any colleges desiring incorporation which were able to satisfy certain requirements designed to test their efficiency and the adequacy of their endowments. By no other scheme would it be possible to secure the advantages which would arise from the establishment of centres of academic training in the centres of population, without incurring the serious risks to which an undue increase in the number of degree-giving universities would expose the whole system of English education.
“Your memorialists believe that such a scheme can only be successfully carried out if the constitution of the university is so framed as to secure to the colleges united with it rights and privileges depending only on their magnitude and efficiency.
“Your memorialists consider that the suggestions of the memorial presented to your lordships by the Owens College, Manchester, that a charter be granted to the Governing Body of the Owens College (with modifications), and that the university be called the University of Manchester, are not calculated to attain this end. They believe that if granted they would prove injurious to other colleges, and that they are incompatible with the position which any particular college or district should occupy in a university based on the principle of federation.
“Your memorialists, for the reasons above stated, humbly pray your lordships to advise Her Majesty, if she is pleased to create a new University, not to grant the charter