84 



PROCESS OF WHITENING PINS AND NEEDLES MADE OP IRON AND STEEL. 



[1854. 



An Iron Coffer Dam. 



In a report of the proceedings of a. semi-annual meeting of the 

 Cornwall Railway Company in England, embracing the report of Mr. 

 Brunei, the Engineer, on the works of the Saltash Bridge, on a part 

 of the line of imtinished railway between Truro and St. Anstell, we 

 find a description of a cott'cr-dam of a novel construction, sunk in a 

 very deep part of the river, to facilitate the construction of a pier for 

 the support of the centre of the bridge which forms a necessary part of 

 the line. The dam in question is not only of a novel structure, but it 

 is made to shut out water to a greater depth than any other work for 

 a similar purpose that we have before seen any account of, viz., a 

 pressure, under high tides, of 70 to 80 feet. It is so constructed as to 

 act as the principle of the diving bell, in case the water should find 

 its way into the inclosure. But it seems to have thus far served its 

 purpose, without a resort to this apparatus. The structure is thus 

 described: 



" It consists of an iron cylinder 37 feet in diameter and 85 in height, 

 containing, within itself all the arrangementsof air chambers, passages, 

 &c. , necessary for using it either as a large diving bell or simply as a 

 coffer dam, as circumstances might require, and so constructed as to 

 be aftenvards divided into two parts vertically, and removed after the 

 pier shall have been built within it. The whole, weighing upwards of 

 three hundred tons, was safely launched and floated into place, where 

 it was raised perpendicularly, and pitched upon its lower edge in the 

 centre of the river. The river is at this point upwards of 50 feet 

 deep at low water of neap tides, and except for a short space on the 

 turn of the tide, there is a considerable current ; under such circiim- 

 stances, this cylinder, was pitched upon its lower edge accurately — 

 that is, within three or fom- inches of the exact point required. Since 

 then the work has been carried on at the bottom of the cylinder, as in 

 a diving bell, against the pressure of water occasionally of 70 and 80 

 feet. The mud and other deposits, forming the bed of the river from 

 10 to 12 feet in thickness, have been removed, and cylinder is now 

 resting on the rock, and preparations are making for excavating the 

 rock into level beds for receiving the masonry." 



The railway of which the branch now under construction, and 

 nearly in readiness to receive the rails, forms a part, is an extension 

 of the line of Great Western, the Bristol and Exeter, and the South 

 Devon Railways, throughout a great part of the county of Cornwall 

 to near the Land's End. — Railway Times. 



FrieiifUy Societies. 



Mr. Finlaison, in the second part of his report upon friendly 

 societies, furnishes very useful and elaborate tables showing the 

 just rates of pecuniary contributions which should be paid in order 

 to secure allowances in sickness, old age, and at death. This 

 report has been prepared at the instance of the Treasury, and it 

 contains so much valuable information that it ought to be care- 

 fully perused and studied by the members of every friendly society in 

 the kingdom. For the ordinary purposes of his calculations Mr. 

 Finlaison divides the population likely to avail themselves of these 

 societies into those engaged in general labour, in light labour, and in 

 heavy labour ; but he observes that nine out of every ten established 

 friendly societies are framed upon the principle of paying to the fund 

 one uniform sum — every man alike, and that any advice for the 

 adoption of a contrary method in the way of a graduated scale is gene- 

 rally received with impatience and treated with neglect. He observes 

 that the half century of time which is comprised between the 16th and 

 66th years of age appears to be precisely the interval of life, during 

 which man is destined to labour ; and that on the general average the 

 sickness for the first 25 years is 182 days, and for the ensuing 25 

 years 362 days, or about one week per annum in the first case and two 

 weeks per annum in the second. The majority of clubs close their 

 doors against new members at the age of 45, and many admit none 

 above 40, but up to these ages, as we have before stated, all who are 

 eligible contribute the same amount. Our able actuary, however, 

 ascertains that between the ages of 15 and 65 a man employed in light 

 labour undergoes but 467 days' sickness, while one employed in heavy 

 labour is visited with 581 days' sickness ; and hence he argues that 

 where the former should pay for allowances in sickness during the 

 working period £1 per annum, the latter ought to pay £1 4s. lOJd., 



or nearly 25 per cent. more. Practically therefore where the common 

 rate of weekly contribution for allowances in sickness is 6d. for the 

 man engaged in light labour, his comrade engaged in heavy labour 

 ought to pay one-fourth more, or 7Jd. This being apparent, Mr. 

 Finlaison recommends that societies should as much as possible limit 

 the members to persons of one or other class of occupation, or, where 

 that cannot be done, that the safe plan would be to adopt for all the 

 rates derived from the experience of those employed in heavy labour, 

 "because," he cautiously and characteristically observes, "those 

 scales which are adopted to the greater risk will always comprehend 

 the less." So much for sickness. The next portion of the report 

 relates to mortality. 



Avf.hage Illness among the Laboukino 'Classes. — Upon this sub- 

 ject Mr. Finlaison, in his second report upon Friendly Societies, affords 

 some interesting information which is worthy of a careful perusal by 

 the managers of those institutions. From the statistics furnished to 

 him he calculates the average number of day's illness per annum suf- 

 fered by the population at different ages. At the age of 45 he states 

 that 99 out of the 100 benefit clubs close their doors to the admission 

 of candidates, and we find that above that age the number of illnesses 

 begin to increase. Between 15 and 16, the average number of days 

 per annum with persons engaged in general labour is 6-^- ; between 16 

 and 26, 6| ; between 26 and 36, 7 ; between 41 and 46, 8f ; between 

 46 and 51, lOJ ; between 51 and 56, 12f ; between 56 and 61, 161; 

 between 61 and 66, 23J ; and between 66 and 71, 36 days. Mr. Finlai- 

 son adds, on an examination of the amount of sickness per annum 

 recorded for the whole mass of the male members of Friendly Societies, 

 from the age of 15 to that of 85, it may be premised that almost exactly 

 five years' sickness is undergone by the man in the 70 years of time. 

 But during the period of labour — that is, from the commencement of 

 the 16th year of age to the close of the 66th — there are in this 51 years 

 biit 78 weeks, or exactly one year and a-half of sickness. Further, 

 that in respect of this period of labour, the sickmess, dui'ing what may 

 almost be termed its second moiety — viz., from the age of 41 to that of 

 66 — is almost exactly the double of that undergone in the previous 

 moiety — from the age of 15 to that of 41 years. For the sickness dur- 

 ing the first 26 years of manhood is exactly half-a-year, or 182A days, 

 while it is 362} days, or almost exactly one whole year, during the 

 »ext ensuing 25 years of maturity. 



Process of -vvliiteiiiiis 



Pins and Needles made of Iron 

 aiid Steel* 



BY MM. VANTILLAED AND LEBLOXD. 



It well known that pins made of brass wire are deficient in 

 strength and elasticity, and accordingly they have been replaced by 

 pins made of iron or steel ; but it is necessary to tin them over. This 

 operation, however, cannot be performed equally well with iron as 

 with brass ; the pins have a rough, uneven surface, which renders 

 them inconvenient to use, as they are liable to tear the cloth. 



Messrs. Vantillard and Leblond, wishing to avoid this defect, 

 formed the idea of first covering the iron with a thin coating of copper 

 or other metal having a gi'eater ajEnity for tin than iron has ; but in 

 order that this result shall be satisfactorily attained, it is necessary to 

 polish and pickle the pins before coppering them. The above named 

 manufacturers have most ingeniously effected the polishing, the pick- 

 ling, and the coppering, by one single operation. To treat for example, 

 2 kilogrames (a little more than 4 lbs. 6^ oz.), 4 litres (about 7 pints) 

 of water, 300 grammes (10 ounces 9 drachms, avoirdupois, by weight) 

 of oil of vitriol, 30 grammes (15 ounces 13 grains, avoirdupois) of 

 white copperas, and 7 grammes (about 108 grains, avoirdupois) 

 of sulphate of copper, are mixed together ; this mixture is allowed to 

 dissolve dm-ing twenty-four hours. The bath being thus prepared, it 

 is to be indroduced into a barrel of wood, made pitcher-like, and 

 mounted upon an axis. Into this barrel, which has a capacity of 

 about 35 pints, the pins are now to be put ; it is then turned rapidly 

 during half an hour, when the pins will be found to have received a 

 pickling, a polishing, and a slight coppering. After the lapse of this 

 time, 20 grammes (about 10 drachms 8 grains avoirdupois) of sulphate 

 of copper in crystals (blue stone), are to be added, and the barrel again 

 turned during 12 minutes, when a solid coppering will be effected with a 

 finely-polished surface. This done, the liquid in the barrel is to be de- 

 canted off, and may be used repeatedly for the same puj'pose : the pins 



