<html>
<html xmlns:v="urn:schemas-microsoft-com:vml" xmlns:o="urn:schemas-microsoft-com:office:office" xmlns:w="urn:schemas-microsoft-com:office:word" xmlns:m="http://schemas.microsoft.com/office/2004/12/omml" xmlns="http://www.w3.org/TR/REC-html40">
<head>
<meta name="Generator" content="Microsoft Word 15 (filtered medium)">
<!--[if !mso]><style>v\:* {behavior:url(#default#VML);}
o\:* {behavior:url(#default#VML);}
w\:* {behavior:url(#default#VML);}
.shape {behavior:url(#default#VML);}
</style><![endif]--><style><!--
/* Font Definitions */
@font-face
{font-family:"Cambria Math";
panose-1:2 4 5 3 5 4 6 3 2 4;}
@font-face
{font-family:Calibri;
panose-1:2 15 5 2 2 2 4 3 2 4;}
@font-face
{font-family:Tahoma;
panose-1:2 11 6 4 3 5 4 4 2 4;}
/* Style Definitions */
p.MsoNormal, li.MsoNormal, div.MsoNormal
{margin:0cm;
margin-bottom:.0001pt;
font-size:11.0pt;
font-family:"Calibri",sans-serif;}
a:link, span.MsoHyperlink
{mso-style-priority:99;
color:blue;
text-decoration:underline;}
a:visited, span.MsoHyperlinkFollowed
{mso-style-priority:99;
color:purple;
text-decoration:underline;}
span.EmailStyle17
{mso-style-type:personal;
font-family:"Calibri",sans-serif;
color:windowtext;}
span.EmailStyle18
{mso-style-type:personal-reply;
font-family:"Calibri",sans-serif;
color:#1F497D;}
.MsoChpDefault
{mso-style-type:export-only;
font-size:10.0pt;}
@page WordSection1
{size:612.0pt 792.0pt;
margin:72.0pt 72.0pt 72.0pt 72.0pt;}
div.WordSection1
{page:WordSection1;}
--></style><!--[if gte mso 9]><xml>
<o:shapedefaults v:ext="edit" spidmax="1026" />
</xml><![endif]--><!--[if gte mso 9]><xml>
<o:shapelayout v:ext="edit">
<o:idmap v:ext="edit" data="1" />
</o:shapelayout></xml><![endif]-->
</head>
<body lang="EN-GB" link="blue" vlink="purple">
<div class="WordSection1">
<p class="MsoNormal"><span style="color:#1F497D;mso-fareast-language:EN-US">Paul,<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D;mso-fareast-language:EN-US">What you describe almost appears to be a loss-loss situation: treat the shells and lose the potential for chemical analysis, don’t treat and lose the potential for morphological description.
<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D;mso-fareast-language:EN-US">I am no malacologist, but the beauty of this forum is that it brings together so many disciplines and perhaps I may be able to contribute from an ‘outsider’s’ point of view.
<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D;mso-fareast-language:EN-US">Various materials require different storage environments. For some collections it has been accepted for decades that it is impossible to keep all materials making up a complete collection
in the same room under the same conditions. Think archaeology, excavated iron objects are so sensitive to corrosion under ‘normal’ museum store conditions that they are usually packaged in microenvironments at, ideally, <10% RH. We treat geological specimens
containing ferrous sulphides in a similar way. <o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D;mso-fareast-language:EN-US">If your mollusc shells would benefit, i.e. suffer less damage, from being stored at higher RH, have you considered storing them in a microenvironment at high RH? We are in the fortunate
position to have a naturally cool and damp room in the sub-basement of the museum building, where we have been storing a number of minerals (for example, polyhydrated sulphates) successfully (i.e. without any damage through dehydration) for several years.
But you can also create microenvironments using saturated salt solutions (see, e.g., Greenspan 1977
<a href="https://urldefense.proofpoint.com/v2/url?u=http-3A__nvlpubs.nist.gov_nistpubs_jres_81A_jresv81An1p89-5FA1b.pdf&d=DwMFAg&c=-dg2m7zWuuDZ0MUcV7Sdqw&r=CLFZJ3fvGSmDp7xK1dNZfh6uGV_h-8NVlo3fXNoRNzI&m=VKQZS6rxG5AJQtsXndEVaqcOUPV6kSpvLi_1WDMi92I&s=r2Se_10ri0OGGh5AMJyd6j525aZxVXTjb91VjhmJEbE&e=">http://nvlpubs.nist.gov/nistpubs/jres/81A/jresv81An1p89_A1b.pdf</a>). There is a question of long-term maintenance, of course, as with any micro environmental storage. Another concern
may be the potential for mould growth, and perhaps the potential for small salt deposits being precipitated on specimens. I have not tried it but it is on my to-do list to find some answers to these questions. If it worked for your shells you may have a way
of preserving both morphological and chemical integrity of your specimens. <o:p>
</o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D;mso-fareast-language:EN-US">Kind regards<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D;mso-fareast-language:EN-US">Christian
<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Tahoma",sans-serif;color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Tahoma",sans-serif;color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><b><span style="font-size:8.0pt;font-family:"Tahoma",sans-serif;color:#1F497D">Christian Baars PhD AMA<o:p></o:p></span></b></p>
<p class="MsoNormal"><span style="font-size:7.0pt;font-family:"Tahoma",sans-serif;color:#1F497D">Senior Preventive Conservator<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:7.0pt;font-family:"Tahoma",sans-serif;color:#1F497D">National Museum Cardiff<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:7.0pt;font-family:"Tahoma",sans-serif;color:#1F497D">Department of Collection Services<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:7.0pt;font-family:"Tahoma",sans-serif;color:#1F497D">Cathays Park, Cardiff CF10 4NP, UK<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:7.0pt;font-family:"Tahoma",sans-serif;color:#1F497D">Telephone: +44 (0)29 2057 3302<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:7.0pt;font-family:"Tahoma",sans-serif;color:#1F497D">E-mail:
<a href="mailto:christian.baars@museumwales.ac.uk"><span style="color:#0563C1">christian.baars@museumwales.ac.uk</span></a>
<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:7.0pt;font-family:"Tahoma",sans-serif;color:#1F497D">Twitter: @NMWPrevCons
<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:7.0pt;font-family:"Tahoma",sans-serif;color:#1F497D">Blog:
<a href="https://urldefense.proofpoint.com/v2/url?u=http-3A__www.museumwales.ac.uk_blog_-3Fcat-3D2484&d=DwMFAg&c=-dg2m7zWuuDZ0MUcV7Sdqw&r=CLFZJ3fvGSmDp7xK1dNZfh6uGV_h-8NVlo3fXNoRNzI&m=VKQZS6rxG5AJQtsXndEVaqcOUPV6kSpvLi_1WDMi92I&s=J99x1LDnP1YF3_PDZ5Bd7KnXO91DDpB7djVp_TAu3Z4&e="><span style="color:#0563C1">http://www.museumwales.ac.uk/blog/?cat=2484</span></a>
<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:7.0pt;font-family:"Tahoma",sans-serif;color:#1F497D"><a href="https://urldefense.proofpoint.com/v2/url?u=https-3A__museum.wales_staff_643_Christian-2DBaars_&d=DwMFAg&c=-dg2m7zWuuDZ0MUcV7Sdqw&r=CLFZJ3fvGSmDp7xK1dNZfh6uGV_h-8NVlo3fXNoRNzI&m=VKQZS6rxG5AJQtsXndEVaqcOUPV6kSpvLi_1WDMi92I&s=ZLCZJZZSEjP3XfhWT-9TjH2LFCkgZeeU_fHg6C3zO3g&e="><span style="color:#0563C1">https://museum.wales/staff/643/Christian-Baars/</span></a>
<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<div>
<div style="border:none;border-top:solid #E1E1E1 1.0pt;padding:3.0pt 0cm 0cm 0cm">
<p class="MsoNormal" style="margin-left:36.0pt"><b><span lang="EN-US">From:</span></b><span lang="EN-US"> nhcoll-l-bounces@mailman.yale.edu [mailto:nhcoll-l-bounces@mailman.yale.edu]
<b>On Behalf Of </b>Callomon,Paul<br>
<b>Sent:</b> 18 May 2017 19:49<br>
<b>To:</b> NH-COLL listserv (nhcoll-l@mailman.yale.edu) <nhcoll-l@mailman.yale.edu><br>
<b>Subject:</b> [Nhcoll-l] To oil or not to oil?<o:p></o:p></span></p>
</div>
</div>
<p class="MsoNormal" style="margin-left:36.0pt"><o:p> </o:p></p>
<p class="MsoNormal" style="margin-left:36.0pt"><span lang="EN-US">(This question is mainly for the managers of mollusk collections, but I’d like to hear from others who might encounter a similar quandary)<o:p></o:p></span></p>
<p class="MsoNormal" style="margin-left:36.0pt"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal" style="margin-left:36.0pt"><span lang="EN-US">The shells of certain mollusks (almost all true mussels [Mytilidae]; pearl oysters [Pterioidea]; pen shells [Pinnidae] and many freshwater mussels) are composed mostly of nacre and have a thick,
bonded periostracum. Removed from the water and placed in a dry environment, they begin to crack and split in a fairly short time. Their nacre can also decay, becoming powdery and weakening with time. The periostracum dries and hardens, and as its modulus
of expansion differs from that of the shell, it begins to flake off or – in the case of thinner shells – to crack the shell. Maintaining humidity at 45-60% year-round should slow this essentially evaporative process, but is unlikely to stop it.<o:p></o:p></span></p>
<p class="MsoNormal" style="margin-left:36.0pt"><span lang="EN-US">A traditional technique to guard against all this is to coat the shells inside and out with a film of mineral oil (Petrolatum). This slows the escape of moisture from the shell matrix and keeps
the periostracum somewhat flexible, and it certainly works; here at the Academy we have oiled freshwater mussel specimens dating back to the 1850s that remain entire. However, oiling is an additive technique and not fully reversible; detergents can remove
the surface film but not purge the shell of oil entirely. <o:p></o:p></span></p>
<p class="MsoNormal" style="margin-left:36.0pt"><span lang="EN-US">The debate, then, is as follows: On the one hand, adding a hydrocarbon to the shell might inhibit or preclude future chemical analysis techniques that we have not yet developed. On the other,
a great deal of work in the mollusca (and many other groups) is based on morphology, and a tray of dust and fragments is of little use in that regard.
<o:p></o:p></span></p>
<p class="MsoNormal" style="margin-left:36.0pt"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal" style="margin-left:36.0pt"><span lang="EN-US">So: in your collection – to oil or not to oil?<o:p></o:p></span></p>
<p class="MsoNormal" style="margin-left:36.0pt"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal" style="margin-left:36.0pt;background:white"><b><span lang="EN-US" style="font-size:10.0pt;color:black">Paul Callomon</span></b><span lang="EN-US" style="font-size:10.0pt;color:black"><br>
<i>Collection Manager, Malacology, Invertebrate Paleontology and General Invertebrates</i></span><span lang="EN-US" style="color:black"><o:p></o:p></span></p>
<div class="MsoNormal" align="center" style="margin-left:36.0pt;text-align:center;background:white">
<span lang="EN-US" style="font-size:10.0pt;color:black">
<hr size="2" width="100%" align="center">
</span></div>
<p class="MsoNormal" style="margin-left:36.0pt;background:white"><b><span lang="EN-US" style="font-size:10.0pt;color:black">Academy of Natural Sciences of Drexel University, Philadelphia<o:p></o:p></span></b></p>
<p class="MsoNormal" style="margin-left:36.0pt;background:white"><span lang="EN-US" style="font-size:10.0pt;color:black">1900 Benjamin Franklin Parkway, Philadelphia PA 19103-1195, USA<br>
<i><a href="mailto:callomon@ansp.org" target="_blank">callomon@ansp.org</a> Tel 215-405-5096 - Fax 215-299-1170</i></span><span lang="EN-US" style="font-size:12.0pt;color:black"><o:p></o:p></span></p>
<p class="MsoNormal" style="margin-left:36.0pt"><span lang="EN-US"><o:p> </o:p></span></p>
</div>
<p> </p>
<p> </p>
<p><span lang="CY" style="font-family: 'Arial',sans-serif;">YMWADIAD<br /> Rydym yn croesawu gohebiaeth yn Gymraeg a Saesneg, ac yn sicrhau y byddwn yn cyfathrebu â chi yn eich iaith ddewisol, boed yn Gymraeg, Saesneg neu’r ddwy, dim ond i chi ein hysbysu. Ni fydd gohebu yn Gymraeg yn peri oedi.</span></p>
<p> </p>
<p><a name="cysill"></a><span lang="CY" style="font-family: 'Arial',sans-serif;">Mae pob neges e-bost a anfonir at neu gan Amgueddfa Cymru yn cael ei <br /> sganio gan systemau diogelwch awtomatig. Sganiwyd y neges hon am firysau cyn ei hanfon, ond dylech hefyd wirio bod y neges, a phob atodiad ynddi, yn rhydd o firysau cyn ei defnyddio. Nid ydym yn derbyn cyfrifoldeb am unrhyw golled neu ddifrod o ganlyniad i agor y neges neu unrhyw atodiadau. Gall y neges hon ac unrhyw ffeiliau a atodir ynddi gynnwys gwybodaeth gyfrinachol a fwriadwyd ar gyfer y derbynnydd yn unig. Os ydych chi wedi derbyn y neges trwy gamgymeriad, hysbyswch ni a dileu’r neges. Safbwyntiau personol yr awdur a fynegir yn y neges hon, ac nid ydynt o reidrwydd yn cynrychioli safbwyntiau Amgueddfa Cymru. Nid ydym yn derbyn cyfrifoldeb am unrhyw wallau, llygredd neu esgeulustod a allai godi wrth drosglwyddo'r neges hon.</span></p>
<p> </p>
<p><span lang="CY" style="font-family: 'Arial',sans-serif;"> </span></p>
<p> </p>
<p style="margin-right: -2.85pt;"><span lang="CY" style="font-family: 'Arial',sans-serif;">DISCLAIMER</span></p>
<p> </p>
<p><span lang="CY" style="font-family: 'Arial',sans-serif;">We welcome correspondence in Welsh and English, and we will ensure that we communicate with you in the language of your choice, whether that’s English, Welsh or both if you let us know which you prefer. Corresponding in Welsh will not lead to any delay.</span></p>
<p> </p>
<p><span style="font-family: 'Arial',sans-serif; mso-ansi-language: EN-GB;">E-mail to and from Amgueddfa Cymru is scanned by automated security systems. This message was scanned for viruses before transmission, but you should also satisfy yourself that the message, and all attachments, are virus-free before use. We can accept no responsibility for any loss or damage that might arise from opening the message or any attachments. This message and any files transmitted with it may contain confidential information intended only for the recipient. If you receive the message by mistake please inform us and delete it. The views expressed in this message are the personal views of the author and may not necessarily represent those of Amgueddfa Cymru. We accept no liability for any errors, corruption or omissions that might arise in transmission of this message.</span></p>
<p> </p>
<p> </p>
<hr />
<p> </p>
<p><br />Scanned by FuseMail.</p></body>
</html>