438 



NATURE 



\AugUSt 2 2, 1878 



tion or ladies' tickets, whilst no new members joined. 



The total sum received by the treasurer for tickets was 



2,605/. Last year the attendance was 1,229, ^.nd the 



sum taken 1,268/. 



The following grants were made : — 



Mathematics and Physics. £ 



Cayley, Prof. — Calculation of Factor Tables for the Fifth 



and Sixth Millions (re-appointed) 150 



Sylvester, Prof. — Tables of Fundamental Invariants of 



Algebraic Forms $0 



Forbes, Prof. G. — Observation of Atmospheric Electricity 



at Madeira (renewed) 15 



Haughton, Rev. Dr. — Tables of Sun-Heat Coefficients 30 



Joule, Dr. — Determination of Mechanical Equivalent of 



Heat (renewed) 65 



Forbes, Prof. — Instrument for Detecting Presence of Fire- 

 damp in Mines 30 



Ayrton, Mr. — Specific Inductive Capacity of a good 



Sprengel Vacuum 40 



Glaisher, Mr. — Luminous Meteors 20 



Gill, Mr. D. — Improvements in Astroncmical Clocks ... 30 



Chemistry. 

 Roberts, Mr. — Composition and Structure of some of 



the less known Alkaloids (re-appointed) 25 



Wallace, Dr. — Development of Light from Coal-gas of 



different qualities (re-appointed) 10 



Adams, Prof. W. G. — Electrolysis of Metallic Solutions 



and Solutions of Compound Salts 25 



Geology. 



Evans, Mr. John. — Exploration of Caves in Borneo ... 50 



Hull, Prof. — Circulation of Underground Waters (re-ap- 

 pointed) 15 



Godwin Austen, Mr. — Kentish Boring Exploration (re- 

 newed) ... 100 



Evans, Mr. John.— Kent's Cavern Exploration (re-ap- 

 pointed) 100 



Evans, Mr. John. — Record of Progress of Geology (re-ap- 

 pointed) 100 



Haughton, Rev. Dr. — Fermanagh Caves Exploration (re- 

 appointed 5 



Close, Rev. Maxwell. — Miocene Flora of Baralt of North 



of Ireland ... 20 



Biology. 

 Bate, Mr. Spence C. — Marine Zoology of South Devon 20 

 Stainton, Mr. — Record of Zoological Literature (re-ap- 

 pointed) ICO 



Foster, Dr. M. — Table at the Zoological Station, Naples 



(re-appointed) 75 



Brooke, Sir Victor. — Illustrations for a Monograph on the 



Mammoth 17 



Sclater, Mr. P. L. — Natural History of Socotra 100 



Rolleston, Prof. — Exploration of Bone Caves in South 



Wales (partly renewed) 50 



Fox, General Lane. — Exploration of Ancient Earthworks 



(re-appointed) 25 



Fox, General Lane. — Excavation at Port Stewart, and 



elsewhere in the North of Ireland 15 



Statistics and Economic Science. 



Farr, Dr. — Anthropometric Committee (re-appointed) ... 50 

 Mechanics. 



Thomson, Sir W. — Datum Level of the Oi'dnance Survey 



(re-appointed) 10 



Froude, Mr. W. — Instruments for Measuring the Speed 



of Ships (renewed) 50 



Napier, Mr. J. R. — Steering of Screw Steamers (re- 

 appointed) 10 



Thomson, Sir W. — Tidal Observations in the English 



Chamael (re-appointed) 10 



KEPORTS. 

 Report of the Committee, consisting of Prof. Cayley, Dr. 

 Farr, Mr. J. W. L. Glaisher, Dr. Pole, Prof. Fuller, Prof 

 A. B. W. Kennedy, Prof. Clifford, and Mr. C. VV. Merri- 

 field, appointed to comider the Advisability and to estimate the 

 Expense of constructing Mr. Babbage's Analytical Machine, and 

 of printing Tables by its means. Drawn up Uy Mr. Merri- 



field. — We desire in the first place to record our obligations to 

 General Henry Babbage for the frank and liberal manner in 

 which he has assisted the Committee, not only by placing at 

 their disposal all the information within his reach, but by ex- 

 hibiting and explaining to them, at no small loss of time and 

 sacrifice of personal convenience, the machinery and papers 

 left by his father, the late Mr. Babbage. Without the valuable 

 aid thus kindly rendered to them by General Babbage it would 

 have been simply impossible for the Committee to have come to 

 any definite conclusions, or to present any useful report. 



We refer to the chapter in Mr. Babbage's " Passages from 

 the Life of a Philosopher," and to General Menabrea's paper,, 

 translated and annotated by Lady Lovelace, in the third volume 

 of "Taylor's Scientific Memoirs," for a general description of 

 the analytical engine. 



The Report then, in Section I., contains an account of the 

 general principles of calculating engines, and proceeds :— 



II. t^pecial Char cuter istics of Mr. Babbagis Analytical 

 Engine. — I. The Mill. — The. fundamental operation of Mr. 

 Babbage's analytical engine is simple addition. This and the 

 other elementary rules of subtraction, multiplication, and divi- 

 sion, and all combinations of these, are performed in what is 

 called ''the mill." All the shifts which have to take place, 

 such as changing addition into subtraction by throwing a re- 

 versing train into gear, or the shift of the decimal place, carry- 

 ing and borrowing, and so forth, arc effected by a system of 

 rotating cams acting upon or actuated by bell-cranks, tangs, and 

 other similar devices commonly used in shifting machinery, 

 sometimes under the name of clutches or escapements. These 

 clutches and bell-cranks control the piu^ely additive and carry- 

 ing processes effected in the additive trains described in the note 

 to Section I., and, being themselves suitably directed, secure that 

 the proper processes shall be performed upon the proper subject- 

 matter of operation, and duly recorded, or used, as may be 

 required. 



2. The Store. — A series of columns, each containing a series 

 of wheels, constitutes the store. This store, which may be in 

 three or more dimensions, both receives the results of operations 

 performed in the mill, and serves as a store for the numbers 

 which are to be used in the mill, whether as original or as fresh 

 subjects of operation in it. Each column in the store corre- 

 sponds to a definite number, to which it is set either automati- 

 cally or by hand, and the number of digits in this number is 

 limited by the number of wheels carried on the shaft of the 

 column. The wheels gear into a series of racks, which can be 

 thrown into or out of gear by means of the card^. 



3. Variable Cards. — All the numbers which are the subject of 

 operation in the mill, whether they are the result of previous 

 operations therein, or new numbers to be operated upon for the 

 first time, are introduced to it in the form of Jacquard ^ cards, 

 such as are used in weaving. One set of wires or axes transfers 

 the numbers on the. e cards to the subject of operation in the 

 mill, exactly as similar cards direct which of the warp threads 

 are to be pushed up, and which down, in tlie Jacquard loom. 

 The mill itself punches such cards when required. 



4. Operation Cards. — A different set of cards selects and pre- 

 scribes the sequence of operations. These act, not upon the 

 number wheels of the mill or store, but upon the cams and 

 clutches which direct the gearing of the.se wheels and trains. 

 Thus, in such an operation as (a ^ -+- c) d, we should require : — 



1st, four variable cards with the nxmibers a, b, c, d. 



2nd, an operation card directing the machine to multiply a 

 and b together. 



3rd, a record of the result, namely, the product a b = p, as a 

 fifth variable card. 



4th, an operation card directing the addition of/ and c. 



5th, a record of the result, namely, the sum/ -f ^ = 17, as a 

 sixth variable card. 



' In a letter ^vritten by Mr. Babbage to Arago in December, 1839, the 

 following explanation of the use of these cards is given. It probably con- 

 veys the idea in the fewest words possible. It is only necessary to add that 

 their twofold employment embodies the separation of the symbols of opera- 

 tion from those of quantity. "You are aware that the system of cards 

 which Jacquard invented are the means by which we can communicate to a 

 very ordinary loom orders to weave any pattern that may be desired. Avail- 

 ing myself of the same beautiful invention, I have by similar means c; mmu- 

 nicated to my calculating engine orders to calculate any formula, however 

 complicated ; but I have also advanced one stage further, and I h^^'s com- 

 municated through the same means orders to follow certain laws in the use 

 of those cards, and thus the calculating engine can solve any equations, 

 eliminate between any number of variables, and perform the highest opera- 

 tions of analysis " 



