62G 
THE ANNUAL CONVERSAZIONE. 
1. Ext. Hyoscyami. 1. Pil. Rhei Comp. 
2. Ext. Conii. 2. Pil. Hydrarg. c, Coloc. 
3. Ext. Coloc. Cotnp. 3. Pil. Ferri Comp. 
The left side to be filled up with infusion jars for the junior dispenser ; the large 
dispensing stock bottles in the drawers not to be repeated, but the sizes varied, 
so that every requisite bottle may be at hand. 
Carre and Company’s ammonia ice-making machine, lent by the agent, Mr. 
Sheppard, of Leadenhall Street, was in operation during the evening, and by 
means of it some ice creams were made, so that the visitors had an opportunity 
of practically testing the quality of the ice produced. This apparatus, the action 
of which depends upon the fact that intense cold is produced by the volatiliza¬ 
tion of ammoniacal gas, consists of two vessels made of iron and hermetically 
closed, which may be compared to a retort and receiver; the retort or boiler, 
having been previously half filled with the strongest liquor ammonise, is heated 
by a charcoal fire or other source of heat, the receiver being cooled by immersion 
in cold water ; under these circumstances the ammonia volatilizes under pressure 
and condenses in the receiver. When the process has been continued for a 
length of time varying from forty-five minutes to one hour and twenty-five 
minutes, according to the size of the machine, the boiler is withdrawn from the 
fire and the receiver from the water, the former is immersed in cold water, while 
the latter is clothed in a flannel jacket, and is exposed to the atmosphere, and 
the water or mixture to be frozen or cooled, having been placed in a tin vessel, 
is dropped into a cavity provided in the centre of the receiver. After the lapse 
of about the same time as was required for the heating process, the tin cylinder 
within the receiver may be withdrawn, when, if water was previously intro¬ 
duced, a block of ice will be found (varying in weight from one to four pounds, 
according to size of apparatus). The ammonia, of course, is never wasted, being 
merely distilled from one vessel to the other, and the expense is therefore very 
trifling. 
Mr. George Lansdown exhibited a model illustrating his patented method of 
communicating between passengers and guards in railway trains. The object of 
this patent is to introduce in the construction and arrangements of railway car¬ 
riages a continuous thoroughfare or way along a train, by the aid of adjustable open 
or enclosed platforms or footways, which shall bridge across the space between 
any two adjoining carriages, leaving free play for the buffers. The proposed 
thoroughfare or way may be either along the interior or exterior, depending 
upon the width of each carriage. The patentee states that the advantages of 
the proposed method of communication are :—1. That it will secure the perfect 
supervision of the whole interior of the train by the guard or attendant in 
charge of the same. 2. That it will combine the convenience and seclusion of 
the English system of railway carriages, with the advantages and protection of 
the American system. 3. That the present railway carriages can be altered in 
accordance with this patent without any very great expenditure, and the new 
carriages, it is believer!, can be constructed without any additional cost. 4. 
That the existing carriages can be gradually replaced by either new or altered 
ones, and thus prevent the necessity of any immediate great change in the pre¬ 
sent system of carriages. 
Messrs. E. B. Bernard and Co. showed in action a working model of their 
Kailway Passengers’ Safety Signal; they state that the advantages this sigual 
possesses are its simplicity of action, and the instaut assistance that can be ob¬ 
tained from the travellers in the adjoining compartment, rendering it unneces¬ 
sary to stop the train, until its arrival at the next station, when the porter, 
seeing the signal exhibited, would prevent any person leaving that compartment 
until satisfied as to the cause of its being used, thus rendering detection certain. 
When the signal is exhibited the bell may be rung until assistance is given. 
